On 10/2/2018 12:51 PM, Lawrence Wilkinson via cctalk wrote: If you look at page B-65 (pdf 189) where it mentions "Start NMI Timeout", there is a bit of hardware you have to add to the design, and set up and control the NMI.? The hardware counts cycles and applies the NMI right after you go to the opcode to be traced, and sends you back into the monitor via NMI. I did a quick scan and didn't see what board they assume for a reference design which may have the NMI trace part of the board. We had an option board which would kill the main firmware and add a debugger, this hardware, and a serial port to a controller we had, which turned any board into a debugging system.? There was another slight mod and a diagnostic firmware we also had on an addon board to allow testing the peripheral we were controlling, and run diagnostics on other hardware. I had a lot of fun getting this monitor going, and a friend implemented a Forth for the diagnostic system for scripting. Thanks Jim

I found this page two days ago - it is a Motorola document for MIKBUG and MINIBUG:includes instructions and source code for both. MINIBUG uses a Motorola ACIA for serial. MIKBUG does bit banged serial through a PIA. http://www.swtpc.com/mholley/MP_A/MIKBUG_Index.htm I am porting MINIBUG to Tektronix 4052A/4054A assembly code (assembler program found on a Tekniques library tape). Here is the link to my thread on vcfed about that Assembler: http://www.vcfed.org/forum/showthread.php?65857-Tektronix-4052A-4054A-Assem… On Tue, Oct 2, 2018 at 6:18 PM Torfinn Ingolfsen via cctalk < cctalk at classiccmp.org> wrote: