140 Series hardware I/O ports


The 140 Series uses memory-mapped I/O. This is located from 0c00h to 0fffh. These are all the ports that I currently know of, and their function, if known.

CPU Boards (7501 or 7684/7685)

0c00
 Z80 CTC Register 0
 R/W
0c01
 Z80 CTC Register 1
 R/W
0c02
 Z80 CTC Register 2
 R/W
0c03
 Z80 CTC Register 3
 R/W
0c04
 SW1 and IPL selection toggle switch
 R
0c05
 SW2
 R
0c06
 MPE (Memory Parity Error) bit register
 R
0c07
 Unknown diagnostic register
 ?
0c08
 Unknown diagnostic register
 ?
0c09
 NMI Generation register
 W
0c0a
 Unknown diagnostic register
 ?
0c0b
 Front panel LED indicators
 W
0c0c
 DS1-DS4, DPB (on CPU board)
 R
0c0d
 CPU board LEDs DS0-DS7
 W
0c0e
 Interrupt generation register (diagnostic)
 W
0c0f
 Unknown
 ?

7685 Memory Expansion

This board resides from 0c20 - 0c2f. I don't know how it works yet.

Floppy/Hawk Controller 7502

0c40
 Status register
 R
0c41
 Disk unit selection register
 R/W
0c42
 Sector counter
 R
0c43
 Load disk head
 W
0c44
 Unload disk head
 W
0c45
 Steps head away from track 0
 W
0c46
 Steps head towards track 0
 W
0c47
 Disk header track number
 R/W
0c48
 Disk header sector number
 R/W
0c49
 Hawk register - Unknown
 ?
0c4a
 Hawk register - Unknown
 ?
0c4b
 Read command
 W
0c4c
 Write command
 W
0c4d
 Write Header command
 W
0c4e
 Diagnostic register
 R/W
0c4f
 Reset controller
 W

Data Link control 7503

0cc0
 Status register
 R
0cc1
 Unit Select
 R/W
0cc2
 Byte transfer low address bits
 R/W
0cc3
 Byte transfer high address bits
 R/W
0cc4
 Data read port (byte)
 R
0cc5
 Unknown
 ?
0cc6
 Device ID/Status register
 R
0cc7
 Data Write port (byte)
 W
0cc8
 Command register
 W
0ccf
 Reset controller
 W

Data Buffer (DMA) 7504

0cd0
 Status register
 R
0cd1
 Source/Target device Unit number
 R/W
0cd2
 Unused
0cd3
 Memory page address
 R/W
0cd4
 Load buffer
 W
0cd5
 Unload buffer
 W
0cd6-0cde
 Unknown
0cdf
 Reset (not sure)
 W

The SMD controller resides from 0c90-0c9f. The Shugart/Quantum controller uses ports 0d00-0d0f.

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