How long did it take to redraw and route the motherboard?
About 3–4 nights, including building a custom parts library in DipTrace [Elektroda, zaxoniec, post #14461445]
Clone Amstrada CPC 464
TL;DR
- A compact clone of the Amstrad CPC 464 microcomputer was built for educational purposes and to save desk space.
- The PCB was redrawn in DipTrace, shrunk to 16x15 cm, and updated with a PS/2 keyboard interface.
- The design replaced the original 40007 chip with the 40010 from the CPC 6128 and initially used the 4164 DRAM chips.
- After wiring fixes and added connections, the prototype booted as a CPC 464, then was converted to a 6128 version with another 64 KB RAM and a new ROM.
- The first prototype had reversed DRAM power wiring, a wrong clock generator, and missing connections; the floppy interface still remains external.
Generated by the language model.
Hello, I would like to introduce my Amstrad 464 microcomputer clone.
Why did I make it? Well, mostly for educational purposes, besides, the original Amstrad 464 is awfully long and takes up a lot of desk space.
Mine takes less. ;)
Diagram: Original diagram of Amstrad 464
I redraw it in the Diptrace program, the record is 16x15 cm. Made in China.
Changes from the original:
I changed the original dedicated chip 40007 used in CPC 464 to 40010 used in CPC 6128.
I added the PS / 2 keyboard interface layout courtesy of my friend Gerald from a friendly forum about CPC (the board in my implementation)
I did not make a layout that supports printer port.
Activation:
After assembling the prototype board, errors appeared, of course.
The basic mistake was that I inversely connected the power to the 4164 memory chips (1bit dram). My mistake, because I drew the memory wrong while making the base of elements in Diptrace. Instinctively I assumed that the 16-pin DIP circuit is powered like in the 74xx series.
The second error was that I made the clock signal generator based on the schematic of the first version 464, based on the 7400, and not as in the subsequent versions on the 74hcu04.
On top of that, there were some missing connections.
After corrections by kynar and adding a few "spider" layouts, the album was launched.
After launching the CD as Amstrad 464 and under the pressure of my friendly CPC forum, I converted it to the 6128 version. I added another 64 kb RAM, changed the ROM. Of course, the album looks terrible after such modifications.
The floppy interface is still external but is working on a new board version that will have it. As well as the keyboard, mouse and expansion card slots.
Action videos:
Version 464
https://www.youtube.com/watch?v=51Iymj_V_aY&list=UUq0qTOm1ux2WOhEDPbe0Ofg
Version 6128
https://www.youtube.com/watch?v=CiJKtdmkNKE&list=UUq0qTOm1ux2WOhEDPbe0Ofg
Comments
What were those times when a computer diagram could fit on one sheet of paper :) How long have you been designing the tile? Did you model the original one or did it your own way? [Read more]
I made the records my own way ;) I was going to make a motherboard with the possibility of attaching additional expansion cards. Still CPC and the board like from a PC with sockets. Friends from the Cpc... [Read more]
Consider whether DRAM should be done on two 1Mb bones with 4x256kb organization or on one 128kB ... 256kB SRAM with 8 bit organization. You will save the PCB surface and the complexity of the paths. ... [Read more]
I'm working on it, only in Amstrad the framework is connected differently. Large memory bones require multiplexers and can be too fast. While in the ZX Spectrum or Atari, the existing memories can... [Read more]
There is a tear in the eye. Eccchhh .... those were the times. Nice that someone else will make a clone. Maybe I'll be tempted by myself. Show your schematic with remakes. [Read more]
Good job. Can you write more about this PCB from China? Where? For how much? How long ? How could you take more pictures. Greetings, Qba [Read more]
Beautiful equipment, put into a beautiful housing :) Respect for the colleague, because the workmanship is really like a factory one :) I have a question - what is this "mesh" case called? What can you... [Read more]
Are you using an original drive or a PC? Batch with software from where? [Read more]
I think that I am asking the following question not only on my behalf, but there will be a larger group of people interested. Are you considering making the PCB design available or possibly ordering... [Read more]
I can see by the amount of PM that PCBs from China are interested. Here I wrote about it: http://www.elektroda.pl/rtvforum/topic2911915.html#14160610 As for the rest of the questions. The "housing"... [Read more]
A colleague would have won deals for this alone? What would the cost be if someone from Electrode ordered it? How about start-up help etc.? best regards :) [Read more]
Most deals are up for grabs. Unfortunately, the prices are a bit scary, for example, for the 40010 chip itself, I paid about PLN 120. Overall, it's not a cheap machine. It is possible that, if I get... [Read more]
It is a pity such prices :( But the design is fine. PLN 120 for one system ... May I know why it is so expensive? [Read more]
Because it was only used probably only in Amstrada and made to order, so you can get it only in the form of storage deck chairs. The second is the HD46505SP, but they are easier to buy for around $ 7-10.... [Read more]
How did you connect the VGA monitor, especially the sync signals? A complex synchro comes out of CPC, and the monitor requires H and V separately. [Read more]
This is a TV and monitor in one, connected via SCART. [Read more]
There is also something like Sync On Green. Not every monitor has it, but you can then give a complex sync signal along with a G signal and the rest, R and B normally. [Read more]
This is not a problem because in normal constructions (like Amstrad) these pins are short-circuited and treated as one input / output. [Read more]
Corresponding control of the signals RDl and WRl. However, the 6845 video processor implements DRAM control, and there are address buses switched. If the RAM was not shared between the CPU and VPU, it... [Read more]