(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
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.
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