First, can someone point me to the latest version of the N2HET I2c emulator code and application note. I tried to search for it online, and I found a version of the application note (and someone here pointed me as well) but I can't find the zip file that contains the code. I must have gotten it SOMEWHERE before, but I do wonder if the bugs I am reporting have been fixed!
In any case, there are two bugs in the HET_EMU.c routine. This is the C code that accesses the HET memory to fetch and put data to the I2c bus. Both are in the routine HetI2CGetChar. First, this routine fetches the data from hetRAM1->Instruction[25].Data. This is not correct. The array index should be 0x2c (stated correctly in the application note). In fact it is better to use the instruction label pHET_CleanRecDat_0 in case the HET code changes.
In addition, the supplied HET_EMU.c code does not shift and mask the fetched 32-bit word so all you will get is the ack bit (0x80). In other words, instead of "return((char)(hetRAM1->Instruction[25].Data));" it should be "return((char)((hetRAM1->Instruction[25].Data)>>8) & 0xff);
