In SX Microcontrollers, SX/B Compiler and SX-Key Tool, rwsenser wrote: Hi peter, Yes, I suspect you are right about the conditional compile (#ifdefs, etc.) and the use of comments for the mechanism to pass the assembler code to the SX-KEY. In addition, while testing I hit several issues. Some were bugs of mine, which are in the process of getting fixed. However, I hit one other issue that calls into question this approach of passing SX assembler through the CC1B compiler as comments. In a nutshell, if the #asm .. #endasm (or whatever syntax. /* */ used in code below) is put at the end of the C program then the CC1B listing (used to communicate CC1B2SX and then with the SX-KEY) does not contain the comments! I'll keep looking at this issue, but this will delay things a bit. Anyway, for those interested, a status update. Thanks for the feedback, RW Senser Here is a sample showing the issue: C snippet: bank0 unsigned char hold; bit holdB0 @ hold.0; // bank1 char c; TRISB = 0xfe; // %1111 1110 RB = 0; while (1) { delay(); holdB0 = pinB0; hold++; pinB0 = holdB0; } /**/ becomes in the CC1B output listing: ; pinB0 = holdB0; SB 16.holdB0 CLRB 6.pinB0 SNB 16.holdB0 SETB 6.pinB0 ; } JMP m008 ORG $07FF JMP main END ; *** KEY INFO *** Notice: the /*