6502.org Forum Projects Code Documents Tools Forum
It is currently Sun Nov 24, 2024 5:18 pm

View unanswered posts | View active topics


Board index » 6502.org Users Forum » Hardware

All times are UTC




Post new topic Reply to topic  Page 1 of 1
  [ 6 posts ] 
  Previous topic | Next topic 
Author Message
GlennSmith
PostPosted: Mon Jun 12, 2023 7:08 am 
Offline

Joined: Thu Dec 26, 2002 12:29 pm
Posts: 81
Location: Occitanie, France
Hello all,
My design for my new WorkBench Computer (WBC) is coming along slowly, and I have decided that I really want to offload the CPU and VIA(s) as much as possible from doing bit-banging donkeywork. Dedicated chips exist for doing I2C interfacing (the newer generation devices, like the PCA9663/65 are, on paper, really impressive), but nothing really exists for SPI. As I've some experience with PICs and AVRs I decided to create a challenge and create my own SPI interface device around a PIC24F device. It turned-out that the DIP28 version of the chip I was looking at didn't have enough pins to be useful - so I doubled the challenge to use the 44-pin SMT version.
The H/W design is at a fairly complete phase. The device has an 8-bit // interface for the 6502 side of things, and I am pushing for SPI, I2C and TTL-level "RS232". The firmware in the PIC is yet to be designed - that's the 2nd-next step.
The board is currently laid-out in 80mm x 50mm. Rs and Cs are oversized 'cos I wanted the board to be - with some experience/effort - home solderable. It looks something like the picture below.
So, here's the idea : if anyone else is interested in this idea can they give me a heads-up and I'll gladly share/cooperate. Any feedback on my design is also welcome.
More news soon...
Glenn-in-France


Attachments:
File comment: The schematic
PIC24F_Breakout.pdf [467.1 KiB]
Downloaded 51 times
File comment: The board
PIC24F_Breakout_3D.jpg
PIC24F_Breakout_3D.jpg [ 79.22 KiB | Viewed 738 times ]


Last edited by GlennSmith on Mon Jun 12, 2023 5:51 pm, edited 1 time in total.
Top
 Profile  
Reply with quote  
GARTHWILSON
PostPosted: Mon Jun 12, 2023 7:41 am 
Offline
User avatar

Joined: Fri Aug 30, 2002 1:09 am
Posts: 8546
Location: Southern California
GlennSmith wrote:
, but nothing really exists for SPI.

Well, this could be a good-news/bad-news thing:  There is a 65SPI chip from Daryl (forum name "8BIT") made with a CPLD, at https://sbc.rictor.org/65spi2.html .  Unfortunately he is not providing programmed parts (or at least wasn't, the last I checked), but he provides the source code and object code to program the Atmel ATF1504 CPLD.  So there is a 6502-bus-compatible chip that takes care of everything so you don't have to bit-bang.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?
Top
 Profile  
Reply with quote  
GlennSmith
PostPosted: Mon Jun 12, 2023 7:51 am 
Offline

Joined: Thu Dec 26, 2002 12:29 pm
Posts: 81
Location: Occitanie, France
GARTHWILSON wrote:
GlennSmith wrote:
, but nothing really exists for SPI.

Well, this could be a good-news/bad-news thing:  There is a 65SPI chip from Daryl (forum name "8BIT") made with a CPLD, at https://sbc.rictor.org/65spi2.html .  Unfortunately he is not providing programmed parts (or at least wasn't, the last I checked), but he provides the source code and object code to program the Atmel ATF1504 CPLD.  So there is a 6502-bus-compatible chip that takes care of everything so you don't have to bit-bang.

Hi Garth, you're an early bird! I had seen and analysed Daryl's device, but unfortunately CPLD is where I don't want to go - I think I've got my head around enough different technologies for one life. I want to be able to move ahead with the toolkit I have. That said, I had vowed not to go down SMT road : but the chip mfrs have forced me...
I am basing my design spec around Daryl's feature list, however. I've limited the board to 4 SPI client selects for the moment for real estate reasons, but I could go to 8nif I change my sockets. Thanks for the feedback.
Top
 Profile  
Reply with quote  
GARTHWILSON
PostPosted: Mon Jun 12, 2023 7:56 am 
Offline
User avatar

Joined: Fri Aug 30, 2002 1:09 am
Posts: 8546
Location: Southern California
I'm a late bird.  :lol:   I'm on the west coast of the US, and I am almost never in bed before 2am.

Maybe you could persuade him (or even someone else) to program a batch of parts to sell, and then you could have the ready-made chip without having to get into programming CPLDs yourself.  You'd just receive it in the mail and install it on your board, as if it were not a CPLD at all.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?
Top
 Profile  
Reply with quote  
BigDumbDinosaur
PostPosted: Mon Jun 12, 2023 5:10 pm 
Offline
User avatar

Joined: Thu May 28, 2009 9:46 pm
Posts: 8514
Location: Midwestern USA
GlennSmith wrote:
My design for my new WorkBench Computer (WBC) is coming along slowly...

Another unreadable schematic. <sigh> All I see is an empty rectangle and some bits-and-pieces with nothing to tell me what they are.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!
Top
 Profile  
Reply with quote  
GlennSmith
PostPosted: Mon Jun 12, 2023 5:27 pm 
Offline

Joined: Thu Dec 26, 2002 12:29 pm
Posts: 81
Location: Occitanie, France
BigDumbDinosaur wrote:
Another unreadable schematic. <sigh> All I see is an empty rectangle and some bits-and-pieces with nothing to tell me what they are.

PDF updated for B/W schematic.

_________________
Glenn-in-France
Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  Page 1 of 1
  [ 6 posts ] 

Board index » 6502.org Users Forum » Hardware

All times are UTC


Who is online

Users browsing this forum: No registered users and 49 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
6502.org is an ongoing project by Mike Naberezny and contributors.