With this board, a Raspberry Pi and a TRS-80 floppy disk drive you can rip TRS-80 floppy disks to .dmk files. Works very well with single density disks including many copy-protected disks. Double-density is a work in progress. Works fairly well for non copy-protected disks with verify enabled.
Please email submissions to me at alan.page.ca (@) gmail.com. Photos of your Pi and/or TRS-80 are encouraged. Submissions may be published on this blog, but with email addresses removed. Please indicate if there is any part of your submission you don't want published.
|Prototype PCB Board|
If there is sufficient interest I am willing to build a few more boards and sell them at the cost of materials plus shipping.
Current StatusDMA is working well at 5 MHZ. It is very reliable with FM decoding, marginal for MFM decoding. This appears to be the limit for getting a full track in a continuous chain of DMA blocks. For some unknown reason the DMA chain stalls out at around 128K. I can extend it by clearing the output FIFO but then there is a one microsecond gap which could cause data loss. Faster DMA speeds could be achieved by using multiple overlapping operations. For example, two 8 MHZ request chains covering 2/3 of a revolution each. I would then need to splice the two blocks together on a suitable boundary.
ZIP file of current PCB schematic/layout for KiCad
ZIP file of current source code.