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I have an Olimex A20 board with a special UEXT connector which could connect SPI, I2C and RS 232. I like to use a MOD Zigbee Module from Olimex to communicate via IEEE 802.15.4 standard direct without using Zigbee.

MOD Zigbee Modul: Here the TRx controller MRF24J40-I/ML from Microchip communicates via 4 line SPI with the PIC18F26K20-I/SS. The PIC can be connect via an ICSP interface for programming. The MRF PSI Pins are available as UEXT connector batches, but there are not soldered with pins of the plastic connector itself. So the MRF can not be connected directly. Does anybody know why?

If I do programming via the ICSP with a C code, do I save and execute this code on the MRF or on the PIC?

Maybe somebody could explain this in a few sentences to me. Thanks a lot!

NewBieGermany
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Rewritten answer :

The 4 pins missing on the UEXT connector are indeed the SPI bus. It seems that your module board only have I2C and UART connectivity.

On your module board, there is, as you stated, two micro-controller units : the MRF24J40 and the PIC18F26K20. These two communicate through a SPI bus. You do not have external access to this bus ; it is only intended for internal communication on the module board (EDIT: You have access to the SPI bus when you code the PIC18F26K20). The I2C and UART interface are connected to the PIC. This module have SPI connectivity through the UEXT connector, because it provide direct access to the MRF24J40, without the PIC.

About the programming, the MRF24J40 is not meant to be reprogrammed, and I'm not even sure you can. The PIC18F26K20 is reprogrammable with the ICSP interface, as you mentioned.

As a side note, if you connect the module to a bigger board, you can use 802.15.4 without the PIC (with the other module), by directly driving the MRF24J40 with the A20. You can still use the PIC to offload communication management (and it's probably what you want here).

ElderBug
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