Prduct specificatin. May 2009 ByVac Page 1 f 18
Cntents 1. Dcument Versins...4 2. Intrductin...4 3. Features...4 4. Device Output...4 5. DC and Stepper...4 6. DC Mtr Cntrller...4 6.1. DC Mtr Cnfiguratins...5 7. Stepper Mtr Cntrller...5 7.1. Stepper Mtr Cnfiguratins...5 8. Digital and Analgue Channel...6 9. Pwer Saving...6 10. All Cmmands...6 11. Digital I/O & Analgue...6 11.1. d...6 11.2. v...7 12. DC Mtr Cntrl...7 12.1. Pwer saving...7 12.2. e...7 12.3. y...7 12.4. m...8 12.5. w...8 13. Stepper Mtr Cntrl...9 13.1. c...9 13.2. n...9 13.3. s...9 13.4. p...9 13.5. x... 10 13.6. r... 10 13.7. u... 10 13.8. h... 10 14. Errr cdes Specific t this interface... 10 15. Revisins t the IASI-2 Sectin... 11 16. Intrductin t IASI-2... 11 17. IASI-2 Electrical Interface... 11 18. Serial Cnnectins... 11 19. Start Up... 12 20. Cmmand Frmat... 12 21. Numbers... 12 22. Factry Cnfiguratin... 12 23. Nn/Inverted Mde... 12 24. Cmmands... 12 August 2006 2 f 18 www.byvac.cm
24.1. Cmmand 1... 12 24.2. Cmmand 3... 12 24.3. Cmmand 4... 12 25. Addressable Cmmands... 13 25.1. Summary... 13 25.2. A (0x41)... 13 25.3. B (0x42)... 13 25.4. C... 13 25.5. D... 14 25.6. E... 14 25.7. F... 14 25.8. G... 14 25.9. U... 14 25.10. M... 14 25.11. N... 14 25.12. P... 15 25.13. R... 15 25.14. V... 15 25.15. T... 15 25.16. Z... 15 26. Errr Cdes... 15 27. Cnnecting and Cnfiguratin... 15 27.1. Start Up... 16 28. Micrcntrller Use... 16 28.1. Multiple Devices... 16 29. Restring Factry Defaults... 17 29.1. Sftware... 17 29.2. Hardware... 17 ByVac Page 3 f 18
1. Dcument Versins 1.0 Nvember 2008 Fr versin 1.a 2.0 Additinal ntes fr pwer save circuit 2.a Errr in previus sheets, this device n lnger utputs binary using the * ptin fr any cmmands except the digital input. 2.b Versin 2.a firmware nw is in line with ther IASI mdules 2. Intrductin The DC mtr cntrller is a dual purpse device capable f cntrlling bth DC mtrs and Stepper mtrs. In additin t this there are tw general prpse digital input / utput lines and 10 bit ne analgue input. As this is an IASI2 device all cntrl is affected by simple single character text cmmands. Sftware is built in fr Pulse Width Mdulatin (PWM) when cntrlling DC mtrs and als step rates and ramp up etc. when cntrlling stepper mtrs. The uses the L293D bridge driver which is capable f cntrlling 2 DC mtrs in frward and reverse r 4 DC mtrs in ne directin. When used fr a stepper mtr the can cntrl either a bi-plar (4 wire) r a uni-plar (5 & 6 wire) type stepper mtr. 3. Features Easy t use asynchrnus serial interface requiring nly 4 cnnectins. Cmmand set based n text Only 2 data lines required, transmit and receive. The device will wrk with transmit nly. Many devices can use the same tw data lines Each device has it s wn user cnfigurable address N specialist hardware, can wrk frm a PC Cm prt Autmatic Baud rate detectin up t 38.4K frm a selected set. Simple sftware requirement fr interfacing with a micrcntrller. Cmmn prtcl used thrughut range, devices can be mixed n same data bus Wrks with RS232 standard vltages and +5V, n level translatr needed fr receiving data Drive current 600mA, up t 36V (ttal pwer 4W) Up t 4 DC mtrs r ne stepper mtr either bi-plar r uni-plar PWM cntrl fr each DC mtr when used in differential mde (frward and reverse) Differential mde, frward and reverse Half step r full step patterns, user definable full step pattern Cntinuus stepping r pre-defined number f steps Step read capability t indicate number f steps t g. Step speed cntrllable frm 128us delay between steps t 32ms in 256 increments. Ramp up available fr slw start. Tw general purpse digital input / utput lines One 10 bit analgue input channel Lw pwer saver mde. 4. Device Output The is basically a serial device that cntrls the L293D integrated circuit that is a 4 channel push-pull driver with built in dide prtectin. It is capable f 1.2A per channel peak and 600mA cntinuus with a suitable heat sink. The PCB prvides sme degree f heat dissipatin but fr higher pwer wrk a heat sink shuld be attached t the back f the IC, this is nt part f the supplied prduct. There are tw pwer supplies t the bard. The lgic supply that shuld be within 4.5V t 6V, this is supplied thrugh pins 3 f the IASI cnnectr and a mtr supply. The mtr supply is n a separate 2 pin cnnectr, this can be any vltage up t 35V t suit the mtr attached. 5. DC and Stepper The is a dual purpse device capable f cntrlling DC mtrs OR a stepper mtr. In additin it has tw general purpse digital lines that can be cnfigured as either input r utput and als ne 10 bit analgue channel. This can be used fr sensing r ther purpses. The next sectins will deal with these in turn. 6. DC Mtr Cntrller Fur channels are available fr cntrlling DC mtrs, YA, YB, YC and YD. Channels can als be paired up t frm differential utputs t enable frward and reverse. YA and YB frm differential utput MA YC and YD frm differential utput MB ByVac Page 4 f 18
There is als tw enable lines assciated with these channels, ENA and ENB. There is a facility t pulse mdulate the enable lines. See the cmmand that deals with pulse mdulatin. 6.1. DC Mtr Cnfiguratins wb this will activate the ENA r ENB lines fr the duty perid. The PWM facility can be disabled s that the ENA and ENB cmmands can directly cntrl the enabling f the YA t YD utputs 7. Stepper Mtr Cntrller The can be used t cntrl up t 4 DC mtrs OR a stepper mtr, nt bth at the same time. All f the channels YA t YD are used t cntrl a stepper mtr, the mtr can be uni-plar r bi-plar. 7.1. Stepper Mtr Cnfiguratins Figure 1 Single Directin Cntrl This cnfiguratin can cntrl up t 4 DC mtrs but in ne directin nly. Figure 4 Bi-plar A bi-plar stepper has 4 wires and they shuld be cnnected as shwn. Figure 2 Differential Cntrl In this cnfiguratin tw mtrs can be cntrlled but in bth frward and reverse directins. All f the cnfiguratins supprt Pulse Width Mdulatin. The PWM has a perid f apprximately 10us. The duty cycle can be adjusted frm 0 t 100% f this by using the WA r WB cmmands. Figure 5 Uni-plar 5 wire Uni-plar mtrs have either 5 r 6 wires. The cmmn line shwn here cnnected t grund can als be cnnected t the mtr pwer supply instead f grund. Figure 3 Duty Cycle & Perid The duty cycle is the active prprtin f the perid. This active perid can be varied. The effect f this is t supply an average pwer utput that can vary the speed f the mtrs. Depending n which cmmand is used wa r ByVac Page 5 f 18
Figure 6 Uni-plar 6 Wire 6 Wire mtrs have tw separate centre tap cnnectins, these can be wired tgether t make an effective 5 wire mtr. 8. Digital and Analgue Channel There are tw general purpse digital channels that can be either set t be input r utput. There is als an 10 bit analgue input channel that can be read as an abslute value 0 1023 r as a percentage value 0 100. See the cmmand fr details f hw there wrk. The reference shuld be taken frm pin 3 f the IASI cnnectr as this is the lgic supply. NOTE als that the analgue input has a 100k pull up resistr cnnected t the +5V rail. Pin Layut 10. All Cmmands All cmmands require t be prefixed with a device address in the range a t z and s any examples given use the default address f a. This device is set t address a n factry reset Cmmand d v Name Digital I/O & Analgue Digital channel A r B Analgue value 0-1023 r as a percentage 0-100 Mtr Cntrl Figure 7 Cnnecting Analgue Example e y m Enable utput YA,YB,YC,YD Set utput YA,TB,YC,YD Differential cntrl Mtr A,B As an example a ptentimeter culd be cnnected t an analgue channel. Nte that ne end f the ptentimeter is cnnected t pin 3 (lgic +5V) and the ther t grund. As usual entering an analgue cmmand, say VA will return a value representing the vltage n pin 2 in text frmat. This is presented at the terminal. 9. Pwer Saving By default, when channel A (ENA) is deactivated (ENA 0) this als deactivates the L293 chip. The net effect is a cnsiderable pwer saving. This hwever may nt be imprtant and may be even undesirable as ENA then effectively acts as a glbal disable. The actin f this is cntrlled by a jumper PW1 n the circuit bard which by default is shrted by a thin PCB track. T disable the actin f ENA cntrlling the pwer t the chip, the track between the jumper, this is n the underside f the bard, shuld be cut. w PWM cntrl A r B Stepper Cntrl c Cntinuus Step r Step Directin m Step Mde n Step number p Step Pattern u Step ramp up s Step Speed x Stp 11. Digital I/O & Analgue 11.1. d Name: Digital Channel A r B Cmmand Parameters:a r b[-][-i][*][1][0] ByVac Page 6 f 18
Typical Use da - Cntrls the digital channel. The channel can be set t either input r utput. At reset the channel is set t input. Issuing the cmmand withut any parameters da r db will return the value n the prt as text, either 0 r 1. Using the cmmand with a star (da*) will return a single binary byte with a value f either 0 r 1. The channel is cnfigured t utput by fllwing the cmmand with dash, this is an fr utput nt a zer. At reset all f the digital channels are cnfigured fr input. When the cannel is cnfigured fr utput, da1 r db1 will set the channel high and da0 r db0 will set the channel lw. P Parameter Table Meaning - Sets the channel t utput -i Sets the channel t input 1 Sets the channel t high when in utput mde, ignred when in input mde 0 Sets the channel t lw when in utput mde, ignred when in input mde Example (assuming device address is a) ada Returns the value n channel A as a text 1 r 0 ada-i value) adb- adb0 Sets channel A t be an input (default Sets channel B t be an utput Sets channel B t utput 0 (lw) 11.2. v Name: Percentage r abslute value fr analgue channel Cmmand Parameters: [p] Typical Use avp The analgue channel is an input and has tw ptins fr the return values. Either as a percentage r as an abslute value. The v cmmand withut the p specified will return the abslute value as a number between 0 and 1023 (10 bits) The p ptin will return a percentage, this is an internal integer calculatin based n a maximum input f 1023. Thus an abslute value f 511 will give a value f 50 when the p ptin is used. The vltage reference used fr this is the +5V lgic supply as cnnected t pin3 f the IASI cnnectr. The cmmand will return a text value representing the value f the analgue vltage. In the abve example if 511 was the value (apprximately 2.38V), fur bytes wuld be returned: 511> 53 (= ASCII 5), 49 (= ASCII 1), 49 (= ASCII 1) and,62 (= ASCII >) will be returned. Example: av Returns the value as an abslute 0-1023 avp Returns the value as a percentage 0-100 12. DC Mtr Cntrl 12.1. Pwer saving Mst f the fllwing cmmands are effected by the pwer saving feature. It is imprtant t realise that the L293 is disabled by default. T enable it, ENA must be enabled. Please remember this when selecting functins fr channel B nly. 12.2. e Name: Enable Mtr Channel A r B Cmmand Parameters: a r b [0][1] Typical Use aea0 The primary functin f this cmmand is t cntrl mtr channel A r B. Mtr channel A cnsists f tw utputs YA and YB, setting this utput t aea0 will disable the utputs, setting aea0 will enable the utputs. Likewise Channel B can be cntrlled by specifying b after the cmmand thus: aeb0 and aeb1 PW Jumper By default channel A has a dual purpse; it nt nly cntrls the selectin f YA/B but is als cntrls a switch that switches ff pwer t the L293. In mst circumstances this is an advantage because f the pwer saving btained. In standby mde the whle circuit nly cnsumes abut 2mA. The actin f this thugh is t disable all f the utputs effectively verriding eb. If this actin is nt desired then there is an ptin t cut the track shrting the PW Jumper n the circuit bard. With the track cut ea n lnger switches f pwer t the L293 chip and can be used as an independent cntrller fr YA/B. The circuit will cnsume mre pwer thugh. 12.3. y Name: Mtr Channel A,B,C r D utput Cmmand Parameters: a,b,c r d [0][1] Typical Use ayb0 ByVac Page 7 f 18
This will set the individual utputs f channels a,b,c r d t either high r lw state. Primarily intended fr cntrlling single mtrs r ther high pwered devices. As marked n the PCB Y1 = b Y2 = a Y3 = d Y4 = c Fr these t wrk the channel als has t be enabled using the e cmmand. 12.4. m Name: Differential Output Cntrl fr mtr channel A r B Cmmand Parameters: a r b [0-4] Typical Use ama3 This cmmand is designed fr cntrlling mtrs as shwn cnnected in Figure 2. When cntrlling a single DC mtr n utputs YA, and YB several things need t happen fr the mtr t g frward, reverse, stp etc. The m cmmand is a useful methd f cntrlling this and effectively cntrls YA,YB and the enable e cmmand accrding t the fllwing table: M[a r b]x ea Y1 Y2 0 0 0 0 1 1 1 0 2 1 0 1 3 1 1 1 4 1 0 0 As can be seen frm the table ma0 r mb0 disables the mtr, ma1 r mb1 drives the mtr ne way, ma2 r mb2 drives it the ther way and 3 r 4 may be used fr breaking r ther effects. Unlike the ther cmmands ma r mb must always be fllwed by a parameter (0-4), ma r mb n its wn will prduce an errr. Example: ama1 this will drive the mtr ne way n channel A (Y1,Y2) amb1 this will drive the mtr ne way n channel B (Y3,Y4) ama2 ama0 this will reverse the mtr n channel A this will stp the mtr n channel A NOTE: If the default pwer saving mde jumper is nt cut then disabling channel A (ama0) will als disable channel B 12.5. w Name: PWM Channel A r B Cmmand Parameters: a 255] Typical Use awa 50 r b [-A][-D][0- The pulse width mdulatr cntrls the enable lines ENA and ENB (WB). The effect f this is t cntrl the speed f a DC mtr. The PWM has a perid f apprximately 10us. The duty cycle can be adjusted frm 0 t 100% f this by using the WA cmmand. PWM Duty Cycle The duty cycle is the active prprtin f the perid. This active perid can be varied. The effect f this is t supply an average pwer utput that can vary the speed f mtrs. During the active perid ENA r ENB is enabled. P -a Activates PWM Parameter Table -d Deactivates PWM 0-255 Meaning Sets the duty cycle within the perid. The larger then number the mre pwer delivered. As the perid fr the mdulatr is apprximately 10us. WA is a value frm 0 t 256 that will vary the n duty cycle n this perid. This is used in cnjunctin with the m cmmand and the enable and Y cmmands. An apprximate calculatin f the length f time ENA will be active is (10/256)*WAus r 0.039 * WA. S if WA is 100 then the mtr will be n fr 3.9us and ff fr 6.1us. The table shws the parameters that can be used with this cmmand. a and -d actives and deactivates the PWM mechanism giving digital (n/ff) cntrl back t the ENA and ENB lines. Star * returns the binary value fr the currently set PWM Value. Example: awa-a Activate PWM fr channel A ByVac Page 8 f 18
awa50 Set PWM t 50 fr channel A Nte the PWM requires enabling befre use with the a switch 13. Stepper Mtr Cntrl 13.1. c Name: Step Cntinuus Cmmand Parameters: [speed directin] Typical Use ac If the cmmand is used n its wn the mtr will cntinually step until a stp cmmand is given ( x ). The speed and directin are taken frm stred parameters set by ther cmmands. As an ptin the speed and directin can be given in this cmmand. If the speed is specified then directin must als be specified. speed is a value frm 0 t 256, the higher the number the less delay between steps and thus the faster the mtr will g. The delay range is calculated by: (255 - speed) * 128us. This gives a minimum delay (max speed) f 128us when speed is 255 and a maximum delay (slwest speed) f 33ms when speed is 0. directin is either 0 r 1 Examples ac 120 1 Cntinuus step, speed 120, directin 1 ac Cntinuus step 13.2. n Name: Step Number f Steps Cmmand Parameters: [x][directin][active] Typical Use an120 Step number f steps specified by x, this is a number in the range f 1 t 32767. N checking is carried ut s numbers utside this range may give unpredictable results. A directin can be specified 0 r 1 Active: When the required number f steps have been reached the mtr will stp and the L293 chip will be disabled by setting the ENA/B enables lines t lw. This is the default actin. There may be a requirement fr the mtr t cme t a 'firm' stp. This can be achieved by leaving the 293 chip energised at the expense f cnsuming current and pssibly heating up the mtr. This can be achieved by setting active t 1. Examples an 120 Step the mtr 120 steps an 120 1 Step the mtr 120 steps in a particular directin an 120 0 Step the mtr 120 steps in the ppsite directin an 120 0 1 Step the mtr 120 steps and leave energised when stpped Specified n its wn it will return the number f steps t g. 13.3. s Name: Step Speed Cmmand Parameters: [0-255] Typical Use as 100 Specifies the step speed fr use with the c r n cmmands. The cmmand n its wn will display the speed setting. Speed is a value frm 0 t 256, the higher the number the less delay between steps and thus the faster the mtr will g. The delay range is calculated by: (255 - speed) * 128us. This gives a minimum delay (max speed) f 128us when speed is 255 and a maximum delay (slwest speed) f 33ms when speed is 0. 13.4. p Name: Step Pattern Cmmand Parameters: [0-F] (hex) Typical Use ap 3 Step pattern applies nly t full stepping mde and is specified as a hex value frm 1 t F. The step patterns is a 4 bit value that the utputs step thrugh in rder t turn n and ff the mtr windings. y1 y3 y2 y4 s1 1 1 0 0 s2 0 1 1 0 s3 0 0 1 1 s4 1 0 0 1 If a step pattern f say 3 is specified using the p cmmand it will give the values in the abve table, the pattern will be 3,9,c,6 and s n this will energise tw cils at a time giving the maximum trque. As an alternative 1 culd be specified fr a step pattern: y1 y3 y2 y4 s1 0 0 0 1 s2 0 0 1 0 s3 0 1 0 0 s4 1 0 0 0 ByVac Page 9 f 18
The abve will nt give as much trque but will use less current. Any pattern can be chsen including 0 that will d nthing at all. Using the cmmand n its wn will return the current step value. 13.5. x Name: Stp Mtr Cmmand Parameters: [1] Typical Use ax Stp the mtr and disable 293 Chip This is a general purpse stp cmmand and by default, withut the parameter will als pull the ENA/B lines lw and switch f the lgic n the chip. Its primary purpse is t stp the stepper mtr after using the c, step cntinuus cmmand. It can hwever be als used with DC mtrs as its actin by disabling the 293 will effectively stp all functins. Using the ptinal parameter will stp the stepping actin f the stepper mtr but leave the 293 enabled thus brining the stepper t a firm hlt and hlding it there. This will cnsume current and may even verheat the mtr if used fr a prlnged perids. 13.6. r Name: Step Directin Cmmand Parameters: [0][1] Typical Use ar 0 reprts r sets the stepping directin. This can be used while the mtr is turning. 0 and 1 are arbitrary directins and depend n hw the mtr is wired. The directin can als be set using the c and n cmmands. 13.7. u Name: Ramp Up Cmmand Parameters: [1-7] Typical Use au 4 Mst stepper mtrs are slw devices. T run at maximum speed it is useful t ramp up the speed ver the perid f a few steps. The ramp up and maximum pssible speed is determined as much by the mechanical envirnment as well as the electrical. The ramp up prvided here is simple but effective. A number is specified between 1 and 7 and the step speed is simply divided by this value ^2. Thus if the step speed is 100 and the SR value is 4, the step values will be as fllws: Step 1 100 / 4^2 = 6 Step 2 100 / 3^2 = 11 Step 3 100 / 2^2 = 25 Step 4 100 / 2 = 50 Step 5 100 = 100 ** There is n ramp dwn. 13.8. h Name: Step Mde Cmmand Parameters: [h][f] Typical Use ah h There is a chice f tw step mdes, half and full. In full step mde there is full cntrl ver the step pattern as defined by the p cmmand. Half step mde uses a table t prduce the fllwing step pattern: y1 y3 y2 y4 s1 1 0 0 0 s2 1 1 0 0 s3 0 1 0 0 s4 0 1 1 0 s5 0 0 1 0 s6 0 0 1 1 s7 0 0 0 1 s8 1 0 0 1 The mde will give a smther, slwer perfrmance frm the mtr. As this is half stepping mde, twice the number f steps will be required fr a full revlutin. 14. Errr cdes Specific t this interface Cde Descriptin nne Data sheet fr the L293 can be fund n the CD- ROM that came with this purchase r alternatively at www.byvac.c.uk ByVac Page 10 f 18
15. Revisins t the IASI-2 Sectin Rev Oct 2008 Change Preliminary 16. Intrductin t IASI-2 The Intelligent Asynchrnus Serial Interface (IASI-2) is a cmmn standard that makes it much easier t cntrl and use hardware frm either a standard cmmunicatin interface (terminal) r a micrcntrller. It is based n a very simple text cmmand set and a flexible hardware and sftware interface. The Intelligent aspect is derived frm the fact that each particular IASI-2 knws abut the cnnected hardware s a simple cmmand can make the hardware perfrm a reasnably cmplex functin. When used in a micrcntrller system this enables the cntrller and designer t cncentrate n the imprtant aspects f the design and cntrl rather than the mundane jb f cntrlling the hardware. It als means that the task f driving cmmn peripherals is nt being cnstantly re-invented. 17. IASI-2 Electrical Interface The device has very simple requirements. A pwer supply, transmit and receive lines as shwn in table E1. The interface is specifically designed s that it can be cnnected t either a standard cm prt (n a PC fr example) r directly t a micrcntrller UART r even a micrcntrller prt pin with a sftware generated UART (Universal Asynchrnus Receiver and Transmitter). A five pin cnnectr is used with nrmally nly 3 r fur pins being cnnected at any ne time. There are TWO receive lines, pin 1 receive line will accept nrmal 5V lgic as presented by a Pin Name Descriptin micrcntrller pin r UART and pin 4 will accept psitive an negative vltages up t 15V that are nrmally present n a standard RS232 interface. Pin 4 will als invert the lgic which is als nrmal fr this interface. The Baud rate is autmatically detected at start up n the first r secnd receipt f Carriage Return (#13). The detectin is frm a fixed set f Baud rates: 9600, 14,400, 19,200 and 38,400. The transmit pin has an pen cllectr utput that has a pull-up resistr n bard cnnected thrugh a jumper. Where mre than ne device is used n the same serial line, nly ne jumper shuld be shrted. See the sectin n multiple devices fr further infrmatin. 18. Serial Cnnectins The device is designed t wrk in either f tw mdes: an INVETED mde fr cnnecting directly t an RS232 prt (factry default) r a NON-INVERTED mde fr cnnecting t a micrcntrller UART. As previusly described there are tw inputs, ne fr each alternative interface. On the transmit side (utput frm the interface) there is nly ne pin that takes care f inverted and nn-inverted lgic, this is cnfigured in sftware. The utput is 0 t +5V nly, rather than the RS232 specificatin requiring psitive and negative signals. On mst RS232 specificatin interfaces this will wrk althugh it is nt within the actual RS232 specificatin. Figure 8 Cnnectin t a PC Figure shws the cnnectins t a 9 pin D type 1 RX Receive data in nn-inverted frm at +5V lgic levels. Use this pin fr cnnecting t MAX232 devices r directly t micrcntrllers. 2 TX Transmit (utput) data. This is 0V and +5V, RS232 levels are nt used. Devices will wrk withut this cnnected but n feedback can be received. This pin is cnfigurable in sftware t transmit either nrmal r inverted lgic. (see multiple devices sectin 28.1) 3 +5V Standard 5V pwer t the device 4 RX-Invert Receive data (input) this will accept -12V t +15V vlts in inverted lgic as is nrmally available n a PC Cm prt. The frmat is RS232 1 start bit 8 data bits and 2 stp bits. 5 GND Grund Table E1 Serial Cnnectin Details ByVac Page 11 f 18
cnnectr fund n mst PC s. 19. Start Up The interface will wait fr a Carriage Return (#13) frm either the inverted r nn-inverted input in rder fr it t establish a Baud rate. The Baud rate is determined frm a fixed range 9600, 14,400, 19,200 and 38,400. N feedback is given and s it is pssible wise t send mre then ne CR just in case. Once the Baud rate has been established the interface is ready t receive cmmands. 20. Cmmand Frmat All devices have an address which is ne byte in the range 97 t 122 (0x61 t 0x7A), this crrespnds t the printable ASCII characters a t z The default address is a and all devices must be addressed althugh there are sme glbal cmmands that address all f the devices at nce. There are basically tw sets f cmmands, thse which are cmmn t all devices, these are usually bytes that crrespnd t upper case characters A Z and there are device specific cmmands using higher values that crrespnd t lwer case characters a z. This sectin deals with the system cmmands. 21. Numbers Sme cmmands require an ASCII cded number and ther cmmands require a byte, fr example when specifying the brightness f the LED display the cmmand is aj4. a Is the address j Is the brightness cmmand and 4 Is the value f the brightness. This cmmand is specified as an ASCII cde s the actual bytes sent t the LED device is: 97 (a) 106 (j) 52 (4) Nte that the 4 is sent as byte 52 (0x34) and nt the byte 4. This is cnvenient when directly typing cmmands at a terminal but can cause cnfusin when using cde. As a generalisatin if a byte value is required then the cde will be smething like: Send(#4) But if an ASCII cded cmmend is required as in the abve example, it wuld prbably be sent as text: Send( aj4 ); 22. Factry Cnfiguratin When an IASIM (Intelligent Asynchrnus Serial Interface Mdule) leaves the factry it is usually cnfigured t address a Factry settings can be restred nrmally by shrting tw cnnectins with a piece f wire and cycling the pwer. 23. Nn/Inverted Mde As previusly mentined the device is capable f perating with a standard RS232 cmmunicatin prt (inverted) and a micrcntrller (nninverted). The device will accept either signal but will utput nly ne and at reset this is inverted 24. Cmmands The interface is cmpletely sftware driven, all cmmands and cnfiguratin are dne thrugh a serial interface. The nly exceptin t this is the hardware factry default restre. When a cmmand has successfully cmpleted it will return the byte value 62 (0x3e) (displayed value > ) This can be detected by sftware as an acknwledgement (ACK). There are a few special cmmands that enable discvery f the devices and system wide defaults. 24.1. Cmmand 1 This is the discvery cmmand and it is a byte with a value f 1 that needs t be sent t the device, this can be dne n a terminal by (Ctrl- A). On receiving this, the device will send back its address. This hwever is dne in a timely fashin with address a being sent first and z last. Each device has 30ms t send its address and will wait its turn, therefre the device with address z will wait 26x30=780ms t send its address. The address is sent alng with the ACK > As an example if 3 devices were cnnected t the bus a, f and p the respnse t cmmand 1 wuld be: a>f>p> 24.2. Cmmand 3 This will reset all devices as if they had just been pwered up. Fllwing this cmmand ne r tw CR is required t establish the Baud rate. 24.3. Cmmand 4 At reset the utput frm the device will be inverted, this cmmand will set all devices t nn-inverted. This cmmand shuld be used if the devices are cnnected t a micrcntrller. Or if a USB-TTL (BV101) type device is being used. The start up sequence fr example wuld be: ByVac Page 12 f 18
CR CR Cmmand 4 ; t establish baud rate ; t set nn-invert At this pint a discvery cmmand (1) culd be sent t see if all f the expected devices are wrking. 25. Addressable Cmmands The next blck f cmmands are directed at a single device and s need an address befre sending the cmmand. The default address f a device is 97 ( a ) By cnventin these cmmands are in the range 65 t 90 giving a printable character f A t Z, this makes it easier fr text input if required. 25.1. Summary Cmmand A B C D E F G U M N P R V T Z Descriptin Address Write t EEPROM Turn ff ACK Delay Turn ff errr reprting Factry reset Read EEPROM Unlck Macr run at start up Switch t nn-inverted Print cntents f EEPROM Reset device Versin Test macr Create macr Nte that examples will use the default address f a and the address and cmmands will be shwn as their ASCII cde because these can be entered directly frm a terminal. The device hwever will nly recgnise the byte value s when aa is entered the device will see tw bytes 97 and 65 25.2. A (0x41) Name: Address Cmmand Parameters: byte 97-122 Typical use aap This cmmand is used t set the address f the device. The address is ne byte with a value f between 97 and 122, giving 26 pssible addresses. The range has been chsen because it renders the values as printable characters in the range a t z. T set a device frm its default address t address p : au aap If this is successful the device will return byte value 0x3e which is the ASCII cde fr > Nte that this cmmand requires an unlck (au) befre it can be issued, this is a safeguard t prevent the device frm unexpectedly changing the address. The address is stred at lcatin 0 f the EERPOM see cmmand B. When a device is used with ther devices n the same bus the addresses must be set up individually befre placing them n the same bus. 25.3. B (0x42) Name: Write t EEPROM as text Cmmand Parameters: <address><space> text Typical use ab10 Hell This device has an internal EEPROM with an address range 0 t 255. Sme f the addresses are used fr system and macr strage s care must be taken where this text ges. N check is made that the system r macr area is being verwritten, the first 16 bytes are reserved fr system use s verwriting this may necessitate a hardware factry reset. The macr area starts at 0xB0 s if there is a macr defined then this shuld be avided. The cmmand frmat is ab<address><space> text Where <address> is the starting address f the EEPROM between 0 and 256. There must be a space between the starting EEPROM address and the single text qute. Nte that this is a single qute (0x27). The text is written and the cmmand appends a 0 nt the end f it s it will ccupy ne extra EEPROM space. Hell fr example wuld be stred as: 0x48,0x65,0x6c,0x6c,0x6f,0x0 This is 6 bytes nt 5 as may be expected. 25.4. C Name: Turn ff ACK Cmmand Parameters: Nne Typical use ac Sme devices may be adversely effected by the ACK cmmand r the cntrlling sftware may nt require the ACK #67 byte. This cmmand will suppress the ACK. The device must be reset t turn it back n. ByVac Page 13 f 18
25.5. D Name: Delay Cmmand Parameters: 1-255 Typical use ad50 Pauses the device fr a number f millisecnds. Sme devices may require a small delay between cmmands particularly when used with the macr facility. The delay is nly apprximate and shuld nt be used fr timing purpses. As an example the LCD display required a delay after clearing and cursr hme, s the macr wuld lk like this: azac1;ad50;at Hell ; 25.6. E Name: Turn ff errr reprting Cmmand Parameters: nne Typical Use ae By default errr reprting is enabled and this will be reprted and an utput prefixed by Errr, fr example Errr 2. This may get in the way f the prgram trying t cntrl the device and s it can be disabled with this cmmand. The nly way t enable it again is by resetting the device. Example: ae. 25.7. F Name: Factry reset Cmmand Parameters: YeS Typical Use afyes Sets the device back t the factry defaults, the cmmand must be fllwed by bytes 0x59, 0x65 and 0x53 which is the ASCII cdes fr Y e S This will prmpt n cmpletin and will nt require re-initialisatin, the address f curse will nw be a. 25.8. G Name: Read EEPROM Cmmand Parameters: agss nn Typical Use ag0 3 The EEPROM values can be read with this cmmand. ss is the start address f the EEPROM in hex nn is the number f bytes t read in hex This cmmand will accept ss and nn as number text values, this means that fr the cmmand: ag10 3 The actual bytes sent t the device are: 0x61,0x47,0x31,0x30,0x20,0x33 Nte hw the 10 fr the start address f the EEROM is specified as 0x31,0x30 which is the ASCII cde fr 10. In a similar way the cmmand returns the values as text. Example: ag0 3 Will typically return: 610DFF> 25.9. U Name: Unlck Cmmand Parameters: nne Typical Use au The unlck cmmand is required fr certain ther cmmands that may change the way the device wrks. It is a safeguard frm accidentally issuing a cmmand, change f address fr example. 25.10. M Name: Run macr at start up Cmmand Parameters: 1 [0 r nthing] Typical Use am1 Macr cmmands are stred at 0xB0 nwards n the EEPROM. This cmmand will set a flag in EEPROM that will be detected by the start up prcedure and run the macr. The macr will be run befre the aut Baud detectin. Once activated the cmmand will always be run s care shuld be taken t test the macr (cmmand T) befre using this cmmand therwise a hardware factry reset may be required. T activate macr at start up issue am1, t turn ff macr at start up issue am0 r just am. Nte the 1 and 0 are text numbers, i.e 0x31 r 0x30 25.11. N Name: Nn-Inverted utput Cmmand Parameters: nne Typical Use an Pin 2 n the electrical interface that supplies the utput infrmatin (Tx line), can be supplied inverted (at reset, start up) r nn-inverted. Inverted is used if the device is cnnected directly t an RS232 PC Cm. prt and nninverted is used when the device ges thrugh a cnverter (BV201, BV101) r is cnnected t a micrcntrller. At reset the device is always in the inverted mde. T set the device t nn-inverted use an, reset is required t set the device back t inverted mde again. ByVac Page 14 f 18
This cmmand is similar t Cmmand 4 except this acts n a device individually whereas cmmand 4 will set all f the devices n the same bus t nn-inverted. 25.12. P Name: Print cntents f EEPROM Cmmand Parameters: <start address> Typical use ap10 This will take the cntents f the EEPROM at the given starting address and utput the data t Tx (pin 2) as raw data (bytes) unlike the G cmmand that will utput the data as text numbers. The cmmand will stp utputting either when it reaches a value f 0 in the EEPROM r when the end f the EEPROM (255) is reached. This cmmand is the ppsite f the B cmmand, the B cmmand will write text t the EEPROM and this cmmand will read and utput it. The start address f the message lcatin within the EEPROM needs t be specified, e.g. apa0. 25.13. R Name: Reset Cmmand Parameters: nne Typical Use ar Resets and individual device. The baud rate will need establishing again after this cmmand is used. This is similar t cmmand 3 but wrks n a single device. 25.14. V Name: Versin infrmatin Cmmand Parameters: nne Typical Use av This simply returns a sting that cntains the firmware and device versin infrmatin. 25.15. T Name: Test macr Cmmand Parameters: nne Typical Use at Runs the macr. This is created by the Z cmmand. It is wise t test macrs with this cmmand befre using the M cmmand. 25.16. Z Name: Create macr Cmmand Parameters: see text Typical Use azac1;at Fred A macr is created at 0xB0 in the EEPROM space and s if it is used, it is up t the user nt t write ver it. The whle macr must be specified n ne line (maximum number f bytes 63) and ';' (semicln) are used t separate cmmands, they are interpreted as EOL when the macr is running. Example azan;av;ap10; The abve example will change the mde t inverted, print ut the versin number and print a message stred in the EEPROM at address 0x10. Nte that the macr als finishes with a ';'. 26. Errr Cdes Errr cdes will be displayed if the debug level (ZD) is set t greater than 0. Cde Descriptin 2 Unknwn cmmand, the cmmand issued is nt in the cmmand table fr this device. 3 Bad device address, the address specified is utside the address range. 4 Bad number usually caused by specifying a hex number (say D0) when a decimal number is required. 5 N terminating qute, fr example: ab10 Hell wuld give this errr. 6 Cmmand lcked, the cmmand used shuld be unlcked with the U cmmand befre using. 27. Cnnecting and Cnfiguratin Figure 9 Cnnectin wiring The abve wiring diagram shws the cnnectins t a standard PC 9 way cm prt (RS232 cnnectr). Pin 1 f the IASI-2 has n cnnectin as this is used t cnnect t a micrcntrller UART. ByVac Page 15 f 18
The factry defaults will wrk with the abve cnfiguratin. Start HyperTerminal r sme ther terminal sftware, BV Terminal is ideal and can be btained frm www.byvac.cm The fllwing settings shuld be used: Baud rate 9600 Start bits 1 Stp bits 2 Handshake nne Lcal ech n (The Baud rate can be ne f the selected rates, see earlier) Pwer up the device and press return a few times. The device shuld nw be listening. Press CTRL-A, this will send cmmand 1 t the device, the device shuld respnd with a>. At this pint if yu are ging t use multiple devices than this is where yu wuld set the address. T set the address t b fr example the fllwing is required: au aab The first cmmand unlcks and the secnd cmmand sets the device address t b. This can be verified by issuing bv, the firmware versin shuld be returned. 27.1. Start Up It may be that yu want t use the device thrugh a line driver device (MAX232) r micrprcessr UART withut bthering with the PC cm prt cable. This is als pssible. Figure 10 Using nn-inverted The abve illustrates the cnnectins used fr, in this example a BV201 bard that simply translates the PC cm prt t nn-inverted 5V lgic levels. Using a BV101 USB slutin culd be prvided and there wuld be n need fr a separate pwer supply. See www.byvac.c.uk fr these prducts. IASI-2 ALWAYS starts with the utput (Tx pin 2) set t inverted mde. If the abve cnnectins are used then the device r devices need t be changed s that the utput is nn-inverted. This is easily achieved by issuing cmmand 4. Once this cmmand is issued all ut put is then nninverted. Nte that the device will revert back t nninverted if reset r pwered f and n again. This prvides a cnsistent and easy t use interface withut the additinal cmplicatin f cnfiguring the device. 28. Micrcntrller Use The utput frm a micrcntrller UART is nninverted, the Tx pin f the micrcntrller will g t the Rx pin 1 f the IASI-2 device. The start up cde culd cnsist f the fllwing: 1) Set the Baud rate f the UART t match ne f the rated fr IASI-2. 2) Send CR (#13) 3 times: this will establish the Baud rate fr any cnnected device. 3) Issue cmmand 4: this will make all the devices use nn-inverted utput frm nw n. 4) Issue cmmand 1: the devices n the bus will respnd and reply in nn-inverted mde thrugh pin 2. All f the devices are nw ready t be used in the nn-inverted mde. Each time the device is reset, either cmmand N r 4 shuld be used t set the utput t nn-inverted. 28.1. Multiple Devices In bth mdes, inverted and nn-inverted many devices can be cnnected tgether and all will receive the crrect input. The utput hwever n pin 2 is cnnected t an pen cllectr and this must have ONE resistr t cmplete the circuit. This resistr is n each device by default and is permanently cnnected via a PCB shrting track. T cnnect mre than ne device ideally nly ne resistr (ne track shrted) shuld be used, the ther tracks cut t accmmdate this. In practice hwever several devices can be cnnected withut any ill effects. IASI 1 Jumper x IASI -2 Jumper 3 5 1 2 3 5 1 2 3 Cnnect +5V tgether 5 Cnnect Grund tgether 1 Cnnect RX tgether 2 Cnnect TX tgether ByVac Page 16 f 18
The abve illustrates this principle where nly ne jumper is cnnected. A side effect f this is that signalling can nly be btained by pulling the utput lw and s feedback can nly be btained n multiple devices using the nn-inverted mde. 29. Restring Factry Defaults Factry defaults can be restred either by sftware r hardware. The factry default cnditin is: Address = a (#97) CR value = #13 29.1. Sftware Issue the cmmand azyes. 29.2. Hardware This is likely t be needed if yu have accidentally changed the cntents f the first 16 bytes f EEPROM. 1. Pwer dwn the device. 2. Temprarily cnnect the tw hles n the device tgether as shwn. If the picture des nt match exactly, then lk fr 5 hles in a rw, at ne end there will be a square hle, this is hle 1. Cnnect tgether hles 1 and 5. 3. Pwer up the device, this will restre the factry settings. 4. Pwer dwn the device. 5. Remve the shrting link. The device is nw restred t the factry settings. NOTE that if a macr was prgrammed at the factry this will n lnger shw. On an LCD device fr example it will nt shw the ByVac screen as it did when it left the factry, just the cursr will shw. Figure 11 Example Shrting link ByVac Page 17 f 18
ByVac Page 18 f 18