GPIB to/from PIC, need some comments and help...

[GraveYard_Killer]

im currently doing a GPIB firmware for my PIC. I want my PIC to act as the master and I want to control and get reading from my oscilloscope that has GPIB port.

I use a PIC18LF2550 using 11MHz crystal and runs @ 3.3V.

here is my connection to the my device

**broken link removed**

I created a routine that sends ascii characters ended by '0x0A' carriage return but it doesnt seem to work.

so I checked with the scope, the NDAC lines and NFRD lines of the oscilloscope is always high.

i experimented this: even when i change the logic of DAV line (alternating 1 and 0) every one second, the NDAC and NFRD doesnt change. im sure I properly initialized PORTA and PORTB.

// CMCON was configured
// ADCON1 was configured
TRISA=0x06; 
/* =============
bit 0 - DAV - output
bit 1 - NDAC - input
bit 2 - NFRD - input
============= */

I temporarily used ordinary latch switches for the 5 Bus management lines so that I could play with it and dont require much software change. and I used so many combinations of the Bus management settings but I can't get it to work.

The GPIB protocol seems to be simple, but I dont know why I can't get it to work. Maybe im missing something out...

I hope somebody can help me...