On the F1-D Reproduction board the ports FA7E, FB7E/FB7F and FBF6/FBF7 are fully decoded. FB7E/FBF6 is chosen with a link/switch on the PCB.
On the F1-D original device the I/O ports are partially decoded:
'''CPC 464:'''
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Legend:
x = not decoded. don't care, 0 or 1 can be used.
0 = must be 0
1 = must be 1
FDC:
I/O address 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:
I/O address A15-A0:
xxxx x0x0 0xxx xxxr
A10=0, A8=0 and A7=0
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On the board above marked 664 there is a patch wire which disconnects A7 and connects A0A3. This changes the decoding from FB7E/FB7F to FBF6/FBF7for FDC.
FDC:
I/O address 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:
I/O address 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 of the data written to the port controls motor state.
The I/O port decoding for the 6128 specific board is currently unknown.
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