The CableAVR. Jeffrey J. Richardson. Purdue University. February 10, 2003

Transcription

1 The ableavr Jeffrey J. Richardson Purdue University February 10, 2003 Jeffrey J. Richardson Page 1 2/10/2003

2 The ableavr The ableavr is a tool designed to serially program the Atmel In-System Programmable microcontrollers. It consists of a Windows application and a special downloading cable. By utilizing the specialized hardware in the downloading cable, the P application allows the user to read, program, and verify many of the Atmel microcontrollers that are in-system programmable. Figure 1 shows a picture of the actual ableavr available from Progressive Resources LL. Figure 1. The ableavr Figure 2 shows the Windows application used to interface with the ableavr. This application allows the programming of the flash in the microcontroller as well as the other important configuration settings. Figure 2. The ableavr Windows Application The program can be launched like most Windows applications by either doubleclicking on the ableavr icon or by selecting the program through the start menu. In the EET lab environment, the program is located under Programs => EET Applications => odevisionavr. Launching the program produces the application shown above in figure 2. Jeffrey J. Richardson Page 2 2/10/2003

3 onnecting the ableavr Software Front-end (able P App) The ableavr Target AVR Figure 3. onnection Diagram The ableavr is connected to the Mega Development board through the ISP connector P3 and the serial port on the host P. Figure 4 below shows a typical Figure 4. AVR Development General Setup view of the general setup. Figures 5 & 6 show a close up view of the actual connections. The DB9 of the ableavr programmer is connected to the DB9 serial cable connected to the P. The 10-pin ribbon cable connector is attached to the ISP port on the MegaAVR development board (note that the JTAG interface uses the same type of connector as the ISP, be sure to use the ISP connector for the ableavr). The actual development board powers the ableavr. The power supply should be set between 8 and 12 volts for normal use in the laboratory environment. 1. ISP Programming Port Label Figure 5. Serial onnection Figure 6. ISP onnection Jeffrey J. Richardson Page 3 2/10/2003

4 onfiguring the Windows Application The P application utilizes one of the P s serial ports to communicate with the ableavr ISP hardware. The Windows application will remember the settings for this application. However, there are no guarantees that the setting will be correct when the application is first started. Therefore, the user must check, at least the first time, the serial port settings to ensure communications with the ableavr. Select the onnection pull down menu and then the Select Port 1. Select the onnection Pull-Down Menu 2. Select the proper port Figure 7. onnection Pull Down Menu 3. Verify onnection 4. Finish Figure 8. omm Setup option to produce the window shown in figure 7. After selecting the proper communication port (OM 2 for EET Lab use), the user should test the connection with the heck button. Once the connection has been verified, the window can be closed by selecting the OK button. Jeffrey J. Richardson Page 4 2/10/2003

5 Selecting the Microcontroller In order for the ableavr to operate properly, the Windows application must know which AVR family microcontroller it is connected with. This can be accomplished in one of two ways. The user can either select the Auto Detect option or manually select the device. The factory setting or configuration of the chip may not allow the device to be automatically detected the first time the user tries to program the chip. Therefore, it is recommended that the user manually select the device from the list of available devices the first time a particular microcontroller is programmed. This is accomplished by using the selection button located next to the device type (see figure 8 ). The user may need to scroll down the list to find the proper device. Once the device is located, the user should click on the device type to select it. Manual Selection Automatic Selection 1. Auto Detecting a device 1. Manually selecting the device type 3. Select the device type from the list 2. Scroll up and down if necessary Figure 9. Selecting the Device Type Jeffrey J. Richardson Page 5 2/10/2003

6 onfiguring the Fuse Bits The AVR family of microcontrollers has certain bits that must either be set or cleared to enable or disable some of the features of the chip. This section guides the user through the setup of these bits. This procedure need only be performed the first time that a microcontroller is used. Once programmed, these settings will remain constant until reprogrammed by the user. Select the Special Options button located under the Device Type to enter the special options window. 1. Select Special Options A brown out occurs when the supply voltage drops below the normal value. In order for the microcontroller to operate properly when this condition occurs, the brown out configuration bits must be programmed. The ATmega16 has a special interface Figure 10. onfiguring the Fuse Bits called a JTAG that is located on Port of the microcontroller. Since EET does not normally use this function, disable the JTAG interface by making certain that the configuration bit is not checked (unless the instructions state otherwise). The MegaAVR Development board used in this class comes with an external clock oscillator. In order to program the device properly, the Reset and lock Selection must be set to use the external oscillator (this also allows the Auto Detection to operate correctly) with the BOD enabled. Once the bits are checked, select the Write button. The Write and Read button labels will turn gray until the procedure has completed. 1. Select Ext. lock 2. Enable Brown Out 6. Write new configuration 3. Set BOD Level 4. Disable the JTAG Interface 7. lose the Special Options 5. Disable BOOTRST Figure 11. Special Option Settings Jeffrey J. Richardson Page 6 2/10/2003

7 Device Parameters In order to save time when programming the selected AVR device, some options may be eliminated under the Device Parameters. It is not a necessity to check the device signature prior to programming, but since this option does not require a significant amount of time, leave this option enabled. To save time while programming, the option to Blank heck the device can be skipped. Since the goal is to program the AVR device, the program code option must be selected. The verify code option can be skipped to save additional programming time, but it is recommended to have the flash code verified to ensure proper programming. If the EEPROM is not being used, these options should not be enabled. These options will take a considerable amount of time to program and should be avoided if not used. The program fuses and security bits should also be programmed. It is recommended that the security level be set to none. This will allow the user to read information back from the device at a later time. 1. heck the signature 2. No Blank heck 3. Program Flash and Verify 4. No Security 4. Fuse and Security Figure 12. Device Parameters 5. No EEPROM selections Jeffrey J. Richardson Page 7 2/10/2003

8 Loading the Hex File Once the environment for the programmer has been configured, the actual program must be loaded into the programmer. To start the process, select the Browse button under the Flash Program Area. The programmer uses standard windows navigation to aid in locating the source file. Once the Hex file has been located, select it by double-clicking or using the Open button. 2. Standard Navigation 1. Select Browse 3. Select the file Figure 13. Opening a Hex File 4. Open the file once selected (or Double-lick on File Name) After the file has been selected, the file must be loaded by selecting the Load button. The relative size of the code will be shown in a percentage of the total amount of Flash available once it is loaded. 2. File Size Figure 14. Loading the Hex File 1. Load the File Jeffrey J. Richardson Page 8 2/10/2003

9 Programming the AVR After the source Hex file has been successfully loaded into the programmer, the software must be programmed into the target AVR. This is accomplished by 1. Select the Program Button Figure 15. Program Button clicking the Program button. Once started, the ableavr will erase the target AVR microcontroller (the hip Erase status bar will show the progress). Figure 16. hip Erase Jeffrey J. Richardson Page 9 2/10/2003

10 The ableavr will then program the Flash area of the target AVR. The Program Flash status bar will show the progress. Figure 17. Programming the Flash The Flash will then be verified to ensure successful programming. Upon completion, the ableavr software will display a message stating that the target device has been successfully programmed. The target AVR will now be running the user software. lick on the OK button to end the programming cycle. 1. lick to End the Program ycle Figure 18. Device Program omplete Jeffrey J. Richardson Page 10 2/10/2003

11 Re-Programming the AVR During the software development cycle, it is quite common to re-program a microcontroller with a slightly different or newer version of the software that has the same name as the previously programmed code. Since the filename and location of the hex file has already been specified, all the user must do is re-load the file and re-program the file. Once the new software has been compiled, select the Load button. As a quick check to verify that the code has indeed changed, look at the Flash heck Sum just prior to loading the file and once the file has been loaded. In most cases, this value changes when the software changes, however, this not always the case. With the new software loaded, the process is the same as covered under the Programming the AVR section. Select the Program Button and the target AVR will be programmed with the new code (following the steps previously described). 2. heck Sum should change 1. Re-Load 3. Re-Program Figure 19. Re-Programming Acknowledgements: The pictures of the application screens are reprinted courtesy of Progressive Resources LL. Jeffrey J. Richardson Page 11 2/10/2003