techtravels.org

inital results on error correction

While I have yet to actually implement the full-scale error correction as I want to, I did some manual tests today. I basically took a track that I was erroring out on, and swapped in 1-bit away values for the bad bytes.  In some cases, it appeared...

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RTC Progress

RTC appears to be working and keeping the date and time across cold-starts. I picked the Epson RTC-72423 which is about a $6 chip, but is obviously directly compatible with the OKI Semiconductor MSM6242B.  The design...

SX microcontroller with 74HC132

Here’s a picture of the prototype coming together. From the top down on the breadboard, you see a pull-up resistor, on the input that comes in on the yellow wire. The output comes out of the grey wire on the right...

SRAM Frame Buffer is now up and running!

Exciting times for the Hope Badge Computer. Tonight, I’ve worked out most of the kinks with interfacing the new SRAM module which you can see in posts below this, to the J68 soft-core CPU. This means that I can...

sync’ing to the 0x4489 0x4489

Well, this wasn’t as easy as I first imagined. There are some issues: 1> By the time you’ve detected the 4489 4489, it’s too late to do much about it. This is because I’m writing one bit at a...

working on the floppy interface

Well I’m now inline with a data tap, so I have access to all 25 pins on the floppy interface between the amiga and the floppy drive.  I used to attach to the DB23 on the pass-thru port of the floppy drive, but I...

New SRAM PCB is being built

So up to two SRAMs can be installed on this tiny 2″ x 2″ board. To the right is the connector, and the SRAMs are on the left. With current SRAM sizes, you can install 32-megabit SRAMs. That’s 4...