Recent content by djrm

Conway's Life on AIM-65 recreation Hello everyone, here are some notes about my recreation of an AIM-65 together with Scott Baker's CRTC display and the AH5050 rom driving a simple interface to a SD2IEC simulation of a COmmodore 1541 disk drive. Using 6502 MECB boards to make an expanded...

There is a fuzzy image in the CRTC manual showing all the available characters available but I never found a better version. What I have found though is a program to dump the character generator rom as a bitmap. Here is a version of the output with a grid overlay. The program I used was found...

I tried moving some CRTC page zero memory and found a solution, see here: https://forum.vcfed.org/index.php?threads/aim-65-video-output-success.1212813/post-1450785

I have been investigating an incompatibility problem which shows itself when trying to access files using the AH5050 interface when the CRTC is in use. Today I have found a solution which seems to help. The CRTC uses some page zero memory which conflicts with that used by the AH5050, my solution...

Ive been reading up on using forth with disk access in the AIM-65 Forth manual and found the implementation notes for the buffer allocation and R/W dand DISK access words suitable for the WD1770 disk controller interface. I'm hoping these can be amended to suit the AH5050 somehow - I'll need to...

I've had a play using cbmctrl to see how the SD2IDE behaves with relative file creation, everything seems in order using the scrips below, I had to use a binary editor to fill the byte value parameters. I expect another editor could cope with the control characters ok - adding a zero byte upsets...

Thanks, I'll look into this. The record length byte is 0x80 Maybe this is a primitive to access a block from a file for the R/W function. I'll have a stab at understanding the disassembly which access that filename. I now have Forth 1.3 working on my recreation, I have managed to use the editor...

Im looking through the ah5050 rom disassembly trying to understand how the system works using the file 'AH5050 - commented disassembly.txt' as reference. Today I am looking at the possibility of using the Forth interface. There seems to be very little implemented in the rom, so far all I can see...

Unfortunately not, it is simply fixed in place where you see it. The system was an alarm controller intended for to be run 24/7, a serial card and telephone line interface cards are not shown in the photos.

This small prototype board is my AH5050 interface, its connected to a SD2IEC 1545 emulation devic. The board also holds a promicro XUM1544 cbmctrl adapprer for communication with the PC. The PC connectivity has been handy for transfering files to the SDcard and issuing directory listings and...

I found this small program useful to test the AH5050 initialisation, it is a dummy STARTUP file, does nothing but print a message to the screen:

Here are photos of a couple of AIM-65 systems, the first is an original looking Rockwell, the second is a DYnaterm in a 19 inch rack case with expansion backplane. The Rockwell isnt working yet, I took its forth roms roms and put them into another system and proved they were ok. It reminded me...

Greetings Scott, I discovered your design and now have a working display board attached to my AIM-65 recreation. I have wanted to have something with a 6845 chip in it for many years. Thanks for your dedication, it's much appreciated. David.

Greetings, I have put together a transmit and receive driver for my AIM65 recreation, it uses a 6551 ACIA. The receive driver uses an interrupt driven buffer with handshaking patched into the UIN vector. I can now import large text files without corruption. Best regards, David.

Hi Dave, I'll surely have some questions before long, I'm trying to fit INIBAS into a system with crtc display driver and a serial bios. things will need little massaging to fit nicely. Best regards, David.