Search found 7 matches

by Bertrude
28 April 2021, 05:00 - Wed
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Thank you for the detailed response :) I will double check my reset line circuitry. I also took the PCF8584 out of circuit and only hooked up VDD & VSS and then connected the RESET pin to VDD using a 4.7k pull up resistor, and still had the RESET pin registering as low. I'm going to order a new ...
by Bertrude
27 April 2021, 05:20 - Tue
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Thanks for that additional information. I've been working on this project the last month or so, and updated my schematic to reflect the changes you mentioned. Removed /INT Added a resistor when setting pin 12 high as part of the address decoding Added a 12 mhz Clock I also got the MADS assembler run...
by Bertrude
26 March 2021, 00:39 - Fri
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Yup, I used KiCAD and then used Photoshop to add some notes to it. I'm using the same CLK for the 6502 and PCF currently. I don't need to send very much data via the PCF so I thought it should be fine, at least for testing. Would I be able to use another CLK source if i wanted it to be faster? Haha,...
by Bertrude
25 March 2021, 04:39 - Thu
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Thanks for clarifying my questions about the 6502 code :) I'm hoping this weekend I can make some more progress on it. Sorry for the messy photo. Last night I created a schematic for it. Currently I have it wired directly to the 6502 and have it accessible on addresses 6000 - 7FFF. I believe this sh...
by Bertrude
23 March 2021, 04:43 - Tue
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Hello, I've gotten my PCF chip all wired up and I've been testing with the assembly code you've included; however I've ran into a couple of problems. 1) I wanted to clarify what assembler you're using for this code? I'm guessing it's Mad-Assembler (MADS), but I'd like to confirm :D 2) In the "p...
by Bertrude
07 March 2021, 22:49 - Sun
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Sounds great. Thanks for the additional information. I plan on using a 6522 for it. I got it wired up, and am getting ready to power it up to begin testing it :)

I will let you know how it goes!
by Bertrude
06 March 2021, 19:26 - Sat
Forum: Hardware Mods
Topic: A2I2C - I2C bus for Atari
Replies: 12
Views: 46353

Re: A2I2C - I2C bus for Atari

Hi, I just wanted to say this is a really cool project, and you've implemented it beautifully. I'm working on a similar project right now, using a 6502 computer to talk to a PCF8584P and found your 6502 code very helpful for how to initialize the chip. I saw that you're assigning address $55 to the ...