National Semiconductor COP400 Product Development System

I bought a notebook of COP400 development info and disks off ebay. The disks turned out to be 8", so I bought an NEC FD1165A floppy drive. This drive is easier to use than other 8" drives, because it only requires 5V DC and 24V DC, and has a 50-pin DIL connector instead of an edge connector. I found a manual for the FD1165 which is very similar, and the NEC APC System Reference Guide has the pinout info for the FD1165A.

I used a PIC microcontroller to control the drive select, head load, side, direction, step and low write current signals, and read the ready, track 0 and write protect signals. The program steps to each track and waits 1 second; since the disk rotates at 360RPM, that's 6 rotations. I had to replace the 150 ohm termination resistors with 1K to get it to work reliably- the PIC couldn't quite sink enough current to overcome 150 ohms.

I captured the index pulse, read data and step signals with a Saleae Logic 16 at 25MHz. I exported the capture as a CSV file, and wrote a program to decode the FM data and read the file data.

I was able to read all the sectors successfully from 3 of the 4 disks; the 4th has obvious physical damage, so the data may not ever be readable.

COP400 Product Development System User's Manual

COP400 Product Development Software Information

QuikLook User's Manual

COP400 In-Circuit Emulator User's Manual

COP400 PDS diskette format info

program to read the disks

The following diskette archives contain FM-decoded bitstreams of each track (diskbits_s0_tn.bin), a disk-image file (disk.bin), a logfile from the dumping process (floppy.log) and the files from the disk.

COPS Tester PDS Master diskette

COPS Tester PDS Test diskette

COPS Tester ROMCHK diskette

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