16 May
2023
16 May
'23
4:36 p.m.
On 5/16/23 16:04, Fred Cisin via cctalk wrote:
For Jim Brain's Coco disk, my inclination would be to image it on an ISA
machine using the WD controller. but, an argument was made that a flux
transition read might be a way to cut down on the number of reads.
Bear in mind that the datarate of a ST506 MFM hard drive is 5MHz, as
opposed to 500KHz for an 8" MFM floppy, so the sample clock may have to
run quite a bit faster--should not be a problem on any modern MCU.
But also note that the data lines to the drive are *differential* not
single-ended, so you'll also need RS422 receivers as well as proper
termination.
FWIW,
Chuck