SC6928B( 文件编号 :S&CIC0460) LED Driver IC DESCRIPTION FEATURES APPLICATION BLOCK DIAGRAM

Transcription

1 DESCRIPTION 第 1 页共 13 页 SC6928B is an LED Conroller driven on a 1/7o 1/8 duy facor. Eleven segmen oupu lines, six grid oupu lines, 1 segmen/grid oupu lines, one display memory, conrol circui, key scan circui are all incorporaed ino a single chip o build a highly reliable peripheral device for a single chip microcompuer. Serial daa is fed o SC6928B via a four-line serial inerface. W Housed in a 28-pin SO Package, SC6928B pin assignmens and applicaion circui are opimized for easy PCB Layou and cos saving advanages. FEATURES CMOS Technology Low Power Consumpion Muliple Display Modes Key Scanning 8-Sep Dimming Circuiry Serial Inerface for Clock, Daa Inpu, Daa Oupu, Srobe Pins Available in 28-Pin, SOP Package APPLICATION Micro-compuer Peripheral Device VCR se Combi se BLOCK DIAGRAM DI/O OSC R Serial Daa Inerface OSC Conrol Dispaly Memory Timing Generaor Key Marix Memory K1 K2 Dimming Circui SEGMENT DRIVER/ KEY SCAN OUTPUT/ GRID DRIVER SG1/KS1 SG2/KS2 SG3/KS3 SG4/KS4 SG5/KS5 SG6/KS6 SG7/KS7 SG8/KS8 SG9/KS9 SG10/KS10 SG12/GR7 SG13/GR6 SG14/GR5 GR4 GR3 GR2 GR1

2 INPUT/OUTPUT CONFIGURATIONS The schemaic diagrams of he inpu and oupu circuis of he logic secion are shown below. W Inpu Pins:, & DIN Inpu Pins: K1 o K2 Oupu Pins: DOUT, GR1 o GR4 Oupu Pins: SG1 o SG10 Oupu Pins: GR5, GR6 and SG12/GR7 第 2 页共 13 页

3 W PIN CONFIGURATION PIN DESCRIPTION OSC DI/O K1 K2 SG1/KS1 SG2/KS2 SG3/KS3 SG4/KS4 SG5/KS5 SG6/KS6 SG7/KS7 第 3 页共 13 页 IC:SC6928 GR1 GR2 GR3 GR4 SG14/GR5 SG13/GR6 SG12/GR7 SG10/KS10 SG9/KS9 SG8/KS8 Pin Name I/O Descripion Pin No. OSC DI/O K1 o K2 I I/O I I I Oscillaor Inpu Pin A resisor is conneced o his pin o deermine he oscillaion frequency Daa Oupu Pin ( N-Channel, Open-Drain ) or Daa Inpu pin This pin Oupus/Inpu serial daa a he falling(rising) edge of he shif clock. Clock Inpu Pin This pin reads serial daa a he rising edge and oupus daa a he falling edge. Serial Inerface Srobe Pin The daa inpu afer he has fallen is processed as a command When his pin is HIGH, is ignored. Key Daa Inpu Pins. The daa sen o hese pins are lached a he end of he display cycle. ( Inernal Pull-Low Resisor) - Ground Pin 22,25,28 SG1/KS1 o SG10/KS10 O SG12/GR7 osg14/gr5 O Segmen Oupu Pins ( p-channel, open drain ) Also acs as he Key Source Segmen/Grid Oupu Pins ,6 8~17 18~20

4 第 4 页共 13 页 - Power Supply 7,21 GR4 o GR1 O Grid Oupu Pins 23,24,26,27 FUNCTIONAL DESCRIPTION COMMANDS A command is he firs bye ( b0 o b7 ) inpued o SC6928B via he DIN Pin afer pin has changed from HIGH o LOW Sage. If for some reason he Pin is se o HIGH while daa or commands are being ransmied, he serial communicaions is iniialized, and he daa/commands being ransmied are considered invalid. Command 1: Display Mode Seing Commands SC6928B provides 2 display mode seings as shown in he diagram below: As saed earlier a command is he firs one bye ( b0 o b7 ) ransmied o SC6928B via he DIN Pin when is LOW. However, for hese commands, he bi 3 o bi 6 (b2 o b5) are ignored, bi 7 & bi 8 (b6 o b7) are given value of 0. The Display Mode Seing Commands deermine he number of segmens and grids o be used (12 o 11 segmens, 6 o 7 grids). A display command ON mus be execued in order o resume display. If he same mode seing is seleced, no command execuion is ake place, herefore, nohing happens. When Power is urned ON, he 7-grid, 11-segmen modes is seleced. Command 2: Daa Seing Commands The Daa Seing Commands execues he Daa Wrie or Daa Read Modes for SC6928B. The daa Seing Command, he bis 5 and 6 (b4,b5) are ignored, bi 7 (b6) is given he value of 1 while bi 8 (b7) is given he value of 0. Please refer o he diagram below. When power is urned ON, bi 4 o bi 1 (b3 o b0) are given he value of 0. SC6928B KEYMATRIX & KEYINPUT DATA STORAGE RAM SC6928B Key Marix consiss of 10 x 3 array as shown below: W

5 K1 W K2 SG1/ SG2/ SG3/ SG4/ SG5/ SG6/ SG7/ SG8/ SG9/ SG10/ KS1 KS2 KS3 KS4 KS5 KS6 KS7 KS8 KS9 KS10 第 5 页共 13 页 Each daa enered by each key is sored as follows and read by a READ Command, saring from he las significan bi. When he mos significan bi of he daa (b0) has been read, he leas significan bi of he nex daa (b7) is read. Command 3: Address Seing Commands Address Seing Commands are used o se he address of he display memory. The address is considered valid if i has a value of 00H o 0DH. If he address is se o 0EH or higher, he daa is ignored unil a valid address is se. When power is urned ON, he address is se a a 00H. Please refer o he diagram below. DISPALYMODE AND RAMADDRESS Daa ransmied from an exernal device o SC6928B via he serial inerface are sored in he Display RAM and are assigned addresses. The RAM addresses of SC6928B are given below in 8 bis uni.

6 W 第 6 页共 13 页 Command 4: Display Conrol Commands The Display Conrol Commands are used o urn ON or OFF a display. I also used o se he pulse widh. Please refer o he diagram below. When he power is urned ON, a 1/16 Pulse widh is seleced and he displayed is urned OFF (he key scanning is sared). SCANNING AND DISPLAY TIMING The key Scanning and Display Timing diagram is given below. One cycle of key scanning consiss of 2 frames. The daa of he are 10 x 3 marix is sored in he RAM.

7 SG Oupu DIG1 DIG2 DIG3 DIGn DIG1 G1 G2 G3 Gn Tdisplay-500us W SERIAL COMMUNICATION FROMAT 1 Frame=Tdispaly Ö (n+1) 第 7 页共 13 页 Key Scan Daa The following diagram shows he SC6928B serial communicaion forma. The DOUT Pin is an N-channel, opendrain oupu pin, herefore, i is highly recommended ha an exernal pull-up resisor (1 KOhms o 10 KOhms) mus be conneced o DOUT. RECEPTION (Daa/Command Wrie) DIN TRANSMISSION (Daa Read) DIN DOUT where: wai (waiing ime) 1μs b0 b1 b2 b6 b b0 b1 b2 b3 b4 b5 b6 b7 If daa coninues wai Daa Read Command is se b0 b1 b2 b3 b4 b5 Daa Reading Sars I mus be noed ha when he daa is read, he waiing ime ( wai ) beween he rising of he eighh clock ha has se he

8 command and he falling of he firs clock ha has read he daa is greaer or equal o 1μs. SWITCHING CHARACTERISTIC WAVEFORM W SC6928B Swiching Characerisics Waveform is given below. OSC fosc 50% PW DIN DOUT Gn Sn 90% 10% seup 10% TZL TZH PW 90% hold where: PW (Clock Pulse Widh) 400nS seup (Daa Seup Time) 100nS - (Clock-Srobe Time) 1μs TZH (Rise Time) 1μs f osc =Oscillaion Frequency TZL < 1μs Noe: Tes condiion under APPLICATIONS PZL 第 8 页共 13 页 TLZ THZ PLZ PW - PW (Srobe Pulse Widh) 1μs hold (Daa Hold Time) 100nS THZ (Fall Time) 10μs PZL (Propagaion Delay Time) 100nS PLZ (Propagaion Delay Time) 300uS TLZ <10μs THZ ( Pull low risisor=100k ohms, Loading capacior =300pf) TLZ (Pull high risisor =100k ohms, Loading capacior=300pf ) Display memory is updaed by incremening addresses. Please refer o he following diagram.

9 W DIN 第 9 页共 13 页 Command2 Command3 Daa1 Daa n Command1 Command4 where: Command 1: Display Mode Seing Command Command 2: Daa Seing Command Command 3: Address Seing Command Daa 1 o n : Transfer Display Daa (14 Byes max.) Command 4: Display Conrol Command The following diagram shows he waveforms when updaing specific addresses. DIN Command2 Command3 Daa Command 3 where: Command 2 Daa Seing Command Command 3 Address Seing Command Daa Display Daa Daa

10 RECOMMENDED SOFTWARE PROGRAMMING FLOWCHART W Noe: 1. Command 1: Display Mode Commands 2. Command 2: Daa Seing Commands 3. Command 3: Address Seing Commands 4. Command 4: Display Conrol Commands 第 10 页共 13 页 5. When IC power is applied for he firs ime, he conens of he Display RAM is no defined; hus, i is srongly suggesed ha he conens of he Display RAM mus be cleared during he iniial seing.

11 ABSOLUTE MAXIMUM RATINGS (Unless oherwise saed, Ta=25, =0V) 第 11 页共 13 页 Parameer Symbol Raings Uni Supply Volage V DD -0.5 o +7 Vols W Logic Inpu Volage V I -0.5 o V DD +0.5 Vols Driver Oupu Curren I OLGR +250 ma I OHSG -50 ma Maximum Driver Oupu Curren/Toal I TOTAL 400 ma RECOMMENDED OPERATING RANGE (Unless oherwise saed, Ta=-20 o +70, =0V) Parameer Symbol Min. Typ. Max. Uni Logic Supply Volage V DD V Dynamic Curren (see Noe) I DDdyn ma High-Level Inpu Volage V IH 0.8V DD - V DD V Low-Level Inpu Volage V IL 0-0.3V DD V Noe: Tes Condiion: Se Display Conrol Commands = 80H (Display Turn OFF Sae & under no load) ELECTRICAL CHARACTERISTICS (Unless oherwise saed, V DD =5V, =0V, Ta=25 ) Parameer Symbol Tes Condiion Min. Typ. Max. Uni High-Level Oupu Curren Low-Level Oupu Curren IOHSG1 IOHSG2 IOLGR Vo=-2V SG1 o SG10, SG12/GR7 Vo=-3V SG1 o SG12, SG12/GR7 Vo=0.3V GR1 o GR6, SG12/GR ma ma ma Low-Level Oupu Curren IOLDOUT Vo=0.4V ma Segmen High-Level Oupu Curren Tolerance ITOLSG Vo=-3V SG1 o SG10, SG12/GR7 - - ±5 ma High-Level Inpu Volage VIH V DD - 5 V Low-Level Inpu Volage VIL V DD V Oscillaion Frequency fosc R=33 KOhms KHz K1 o K2 Pull Down Resisor RKN K1 o K2 =5V KOhms

12 APPLICATION CIRCUIT V V+ MCU VSS 2.2K 2.2K 2.2K 100uF V+ S1 S2 S3 S4 S5 S6 S7 33K OSC DI/O K1 K2 SG1/KS1 SG2/KS2 SG3/KS3 SG4/KS4 SG5/KS5 SG6/KS6 SG7/KS7 KS10 SW19 SW20 KS9 SW17 SW18 GR1 GR2 GR3 GR4 SG14/GR5 SG13/GR6 SG12/GR7 SG10/KS10 SG9/KS9 SG8/KS8 KS8 SW15 SW16 KS7 G1 G2 G3 G4 G5 G6 S12 S10 S9 S8 SW13 SW14 第 12 页共 13 页 KS6 V+ SW11 SW12 0.1uF KS5 SW9 SW10 KS4 W G1 G2 G3 G4 G5 G6 S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 SW7 SW8 DIGHT1 DIGHT2 DIGHT3 DIGHT4 DIGHT5 DIGHT6 SEG10 SEG9 SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1 Noe: 1 推荐使用时,I 2 C 总线端口外置上接电阻在 2.2K 为宜 ; 2 为降低系统信号的串扰, 建议产品之 MCU 与 SC6928 供电之正极串接 4148 二极体隔离 KS3 SW5 SW6 KS2 SW3 SW4 6-GRID X 12-SEGMENTLED (COMMON CATHODE) KS1 SW1 SW2

13 COMMON CATHODE TYPE LED PANEL: SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 a b c d e f g h COM/DIGITAL (GRID) W 第 13 页共 13 页 f e a g d Noe: 1 The capacior (0.1uF) conneced beween he and he pins mus be locaed as close as possible o he SC6928B chip. 2 The SC6928B power supply is separae from he applicaion sysem power supply. b c h