AVR ISP programmer In-System Programmer

A programmer is available in the "AVR Software and Technical Library - April 2003" CD-ROM and has been published due to its stability and compatibility with AVR Studio 4. It has been tested with the AT90S2313 microcontroller and functioned correctly. To operate this programmer, a 4 MHz crystal must be connected to the slave device at the XTAL1 and XTAL2 pins. Alternatively, if using a device with an internal oscillator (such as AT90S2343, ATmega161, etc.) that is enabled, an external oscillator is not required. Additionally, the MAX232 or MAX202 can be utilized instead of transistors, capacitors, and resistors to connect the master AT90S1200 to a Personal Computer (PC). This hardware configuration has been verified using the MAX202.

The described programmer circuit is designed for use with AVR microcontrollers, specifically targeting devices like the AT90S2313, AT90S2343, and ATmega161. The circuit requires the integration of a 4 MHz crystal oscillator, which is essential for timing operations in microcontroller applications. The crystal should be connected to the XTAL1 and XTAL2 pins of the microcontroller to ensure stable clock generation.

In cases where microcontrollers with internal oscillators are used, such as the AT90S2343 or ATmega161, the external crystal is unnecessary, provided that the internal oscillator is enabled. This feature simplifies the design and reduces component count, thereby enhancing reliability.

For communication between the master microcontroller (AT90S1200) and a PC, the circuit can incorporate either the MAX232 or MAX202 integrated circuits. These components serve as level shifters to convert TTL logic levels to RS-232 levels, facilitating serial communication. The use of these ICs can replace discrete components like transistors, capacitors, and resistors, streamlining the design process and improving performance. The MAX202, in particular, has been tested successfully in this configuration, ensuring robust communication with the PC.

Overall, this programmer circuit exemplifies a well-thought-out design that balances functionality with simplicity, making it an excellent choice for programming AVR microcontrollers.Programmer in my "AVR software and technical Library - April 2003" CD-rom and decide to publish it. The reason was, that this programmer is very stable and works perfect with AVR Studio 4. I hadtested it before published it, with AT90s2313 and its worked fine! To work this programmer you must to connect acrystal 4MHz to slave device at theXTAL1 and XTAL2pins, or if you have an device with internal oscillator (AT90S2343, ATmega161 etc) and its enabled, its not need any external oscillator. If you want you canuse MAX232 or MAX202 instead transistors, capacitors and resistors to connect master AT90S1200 with Personal Computer (PC).

There is no problem (i check this hardware by using MAX202). 🔗 External reference