=== FDC I/O Ports ===
All types of floppy disk controllers for the F1-S/D and M1-S/D series are based on the NEC 765 chip. The manual states that on "controllers having an integrated ROM module/eprommer" (probably On the later 6128 interfaces?), F1-D Reproduction board the port addresses can be freely configured using ports FA7E, FB7E/FB7F and FBF6/FBF7 are fully decoded. FB7E/FBF6 is chosen with a decoder ROMlink/switch on the PCB. On the F1-D device the I/O port is partially decoded:
'''CPC 464:'''
| 0xFA7E || motor on/off
|}
FDC:
A15-A0
xxxx x0x1 0xxx xxxr
A10=0, A8=1 and A7=0
x = not decoded. don't care, 0 or 1 can be used.
r = connected to A0 on NEC765 and selects status register or data register.
Motor:
A15-A0
xxxx x0x0 0xxx xxxr
A10=0, A8=0 and A7=0
x = not decoded. don't care, 0 or 1 can be used.
only bit 0/D0 controls motor state.
'''CPC 664/6128:'''
| 0xFA7E || motor on/off
|}
On the board above marked 664 there is a patch wire which disconnects A7 and connects A0. This changes the decoding from FB7E/FB7F to FBF6/FBF7.
FDC:
A15-A0
xxxx x0x1 xxxx 0xxr
A10=0, A8=1 and A3=0
x = not decoded. don't care, 0 or 1 can be used.
r = connected to A0 on NEC765 and selects status register or data register.
Motor:
A15-A0
xxxx x0x0 0xxx xxxr
A10=0, A8=0 and A7=0
x = not decoded. don't care, 0 or 1 can be used.
only bit 0/D0 controls motor state.
The I/O port decoding for the 6128 specific board is unknown.
=== Downloads ===