Summary of How Do You Make Your AVR Programmer Four Times Faster?
This article introduces a robust JTAG programmer by Kanda for Atmel AVR microcontrollers, offering four times faster programming speeds than traditional ISP methods. It highlights the use of AVR Studio software for debugging and notes that while JTAG is ideal for newer 40+ pin ATmega devices, an adapter allows switching to serial programming for older chips like ATtiny or ATmega8 without changing the setup.
Parts used in the JTAG Programmer Project:
- AVR microcontrollers
- JTAG controller
- Kanda JTAG programmer
- AVR Studio software
- In Circuit Emulation (ICE) hardware
- Adapter for JTAG and serial programming
(PRWEB) August 24, 2005
Up to now AVR microcontrollers have been programmed in a ZIF socket using parallel programming, or have been programmed in circuit using the In System Programming (ISP serial programming) protocol and interface. Now Atmel have provided a third interface using JTAG and Kanda have developed a programmer for it.
The main reason for Atmel adding a JTAG controller to the AVR microcontrollers was to improve In Circuit Emulation of the chips. Atmel and Kanda have exploited this feature very effectively, using the brilliant AVR Studio software as an interface. So now low cost emulators are freely available for AVR, unlike emulators for the PIC, and are very effective for code debugging. For example, look at http://www.kanda.com/products/Kanda/JTAGAVR.html.
Lots of developers are now happy using the JTAG protocol for debugging but tend to stick with the ISP interface for programming. This is because production engineers do not want AVR Studio and fragile ICE hardware on the production line, for obvious reasons. Therefore, Kanda have now introduced a robust JTAG programmer that gives all the benefits of JTAG for the production environment.
The major advantage of the JTAG programming interface over the serial programming interface is its speed. Typical serial programming speeds are about 4KBytes/second while JTAG can manage 16Kbytes/second. This translates to about 8 seconds to program a complete Atmega128.
The JTAG interface is only available on the newer ATmega devices with more than 40 pins, so older AVR devices, ATtiny and smaller ATmega chips, such as the Atmega8, are not supported. This is why Kanda have supplied an adapter and one piece of software for both JTAG and serial programming, so it is easy to swap between programming methods.
So, you can improve programming speeds by a factor of four for devices with a JTAG interface, yet retain the ability to program other AVR devices without any major changes to your setup - same software, same programmer, different interface.
For more information, see
http://www.kanda.com/products/Kanda/AVRUSB-JTAG.html
About Kanda:
Kanda manufacture and supply a wide range of embedded system tools. We are specialists in In System Programming, low cost emulators and training systems for a wide range of microcontrollers, PLDs and memory devices, including PIC, AVR, ST7 and COP8. We also supply interfaces for USB, CAN Bus and serial to Ethernet conversion.
# # #
- What is the main advantage of the JTAG interface over the serial interface?
The JTAG interface offers significantly higher speed, managing 16Kbytes/second compared to the typical 4KBytes/second of serial programming. - How long does it take to program a complete Atmega128 using JTAG?
It takes approximately 8 seconds to program a complete Atmega128 with the JTAG interface. - Which AVR devices support the JTAG interface?
JTAG is only available on newer ATmega devices that have more than 40 pins. - Can I program older AVR devices like the ATtiny or ATmega8 with this system?
Yes, Kanda supplies an adapter and software to allow programming of older devices using the serial interface. - Does the new JTAG programmer require different software than the standard ISP setup?
No, users can retain the same software and programmer, simply switching interfaces via the adapter. - Why do production engineers typically prefer ISP over JTAG for production lines?
Production engineers avoid JTAG because it requires AVR Studio software and fragile ICE hardware which are not suitable for production environments. - What tool does Atmel use to exploit the JTAG controller feature effectively?
Atmel and Kanda utilize the brilliant AVR Studio software as the interface for In Circuit Emulation. - By what factor can programming speeds be improved for JTAG supported devices?
Programming speeds can be improved by a factor of four for devices with a JTAG interface.
