During Retro Challenge I needed a way to run machine code on my rc2014, as BASIC was incapable of the performance needed to initialise the SD card in bitbang mode.
I didn't (and still don't) have an EEPROM burner when I first got my rc2014, and although the version of …
read moreI'm at my deadline for RetroChallenge 2016/10 and unfortunately I'm tantalisingly close to having something that works, but not quite there.
I have the bitbang/slow mode working and generating pulses that match the output I get from my Bus Pirate when using it to talk to the SD …
read moreAs it stands my RetroChallenge entry is close to working, but not quite there.
The fast mode appears to work and I was able to decode the SPI packets sent to the SD card with OpenLogicSniffer's SPI analyser module.
The picture above shows the signals and the decoded data for …
read moreHaving finally found time to start breadboarding my SD card interface I first made sure that the edge trigger circuit I had tested in ModelSim would work when built with real components.
An issue I had encountered previously when breadboarding RC2014 peripherals was that if I wanted to disconnect the …
read moreTo avoid the work done designing my SD interface being wasted I decided to verify the concept before going any further.
I used my Bus Pirate to verify that the SD card I have would respond to the commands I expected using the protocol I expected.
The Bus Pirate supports …
read moreI've been struggling for free time this month for poking around with breadboards and other fun things. To work around this, and still (hopefully) get my RetroChallenge entry done, I decided to use a simulator so I could work on it with my laptop whenever and wherever there was time …
read moreIn my previous post I promised to show the previous implementation of my Z80 SD interface, and to run through the problems which I intend to fix this month.
The 74138 (U1) in the top left of the schematic is used to detect and decode IO reads and writes from …
read moreI decided to join in with ` <http://www.wickensonline.co.uk/retrochallenge-2012sc/>`__Retrochallenge 2016/10 this October. I'm also hoping this will provide some incentive to write more posts and updates about other projects once I'm back into the swing of things!
My goal for this Retrochallenge is to finish …
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