Retro CPC Dongle – Part 32

Well, as promised in my last CPC2 post, I finished the next build of the CPC2 board and learned a lot of things during the process. Somethings worked, some things didn’t, but every build is giving me a wealth of knowledge of product design, fault diagnosis and rectification work. Yes, de-solder braid really was my best friend in this build!

Finally, a working board (click here for large)
Bottom side of board (click here for large)

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Retro CPC Dongle – Part 30

 

“Cache Grab”

Yes, pun intended, this post is about the caching SDRAM controller that I’ve written for the new CPC2.2 board. Here’s the cache (screen) grab:

Cache (Screen) Grab (Click for large)

This screen grab shows one of the key process steps in the caching controller, the cache line replacement. The red bracket indicates the cache i/o ports and some key internal state variables, and the blue bracket indicates the data cache i/o ports on the dual-port ram. Continue reading

Retro CPC Dongle – Part 29

How time flies – it’s been a month since I posted. I’ve been waiting for the PCBs ordered from OSH Park to arrive. They were tracked all the way from the US to my local post office, and somehow Australia Post managed to lose them 😦 The helpful people at OSH Park didn’t hesitate, they put through another copy of my board on the next production run at no cost to me. They’re on their way already – thank you, OSH Park! I can’t rate these guys highly enough!

So, let’s start with the obligatory graphic:

Simulating the SDRAM controller, connected to a Z80! (Click for large)

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Retro CPC Dongle – Part 22

The screen shot below says it all. Yay! Video output from the CPC2.0!

Colour test for HDMI output from CPC2.0 board

I promised myself that I wouldn’t post those shaky photos/videos that people seem to post of their game/emulator/screen. Unfortunately, at this time a photo of the screen is the best I can do. Longer term, I’ll get a HDMI capture card from eBay and capture the screens properly, but for now this will have to do as proof of success! Colour bars. Continue reading