IBM CMX58886CX User Manual
Page 65
BDM-610000050
Rev A
Chapter 4: Using the cpuModule
57
Clear Register
:
A read to this register Clears the IRQs and a write to this register sets the DIO-Compare, DIO- Mask,
DIO-Control, Port 1, and Port 0 to zeros. A write to this register is used to clear the board.
Port 0 Direction Register
:
Writing a zero to a bit in this register makes the corresponding pin of the multiPort connector an input.
Writing a one to a bit in this register makes the corresponding pin of the multiPort connector an output.
Mask Register
:
Writing a zero to a bit in this register will not mask off the corresponding bit in the DIO-Compare register.
Writing a one to a bit in this register masks off the corresponding bit in the DIO-Compare register. When all
bits are masked off the aDIOs comparator is disabled. This condition means Event and Match mode will not
generate an interrupt. This register is used by Event and Match modes.
Compare Register
:
A Read/Write register used for Match Mode. Bit values in this register that are not masked off are compared
against the value on Port 0. A Match or Event causes bit 6 of DIO-Control to be set and if the aDIO is in
Advanced interrupt mode, the Match or Event causes an interrupt.
Table 42
DIO-Control I/O Address 453h—Read Access
D7
D6
D5
D4
D3
D2
D1
D0
Table 43
DIO-Control I/O Address 453h—Write Access
D7
D6
D5
D4
D3
D2
D1
D0
Table 44
Multi-Function at Address 452h
1
1. Contents based on bits D0 and D1 of DIO-Control.
X
X
X
X
X
X
X
X
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
M7
M6
M5
M4
M3
M2
M1
M0
C7
C6
C5
C4
C3
C2
C1
C0
Strobe 0 Status
0 = no strobe
1 = strobe
Digital IRQ Status
0 = no digital interrupt
1 = digital interrupt
Strobe 1 Status
0 = no strobe
1 = strobe
Digital IRQ Mode
00 = Disabled
01 = strobe Mode
10 = event mode
11 = match mode
Port 1 Direction
0 = input
1 = output
Multi-Function
Register Select
00 = clear mode
01 = port 0 direction
10 = mask register
11 = compare register
Multi-Function
Register Select
00 = clear mode
01 = port 0 direction
10 = mask register
11 = compare register
Port 1 Direction
0 = input
1 = output
Reserved
read/write
00 clear
0 in, 1 out
01 Port 0 direction
0 no mask, 1 mask
10 DIO mask
read/write
11 compare
Digital IRQ Mode
00 = Disabled
01 = strobe Mode
10 = event mode
11 = match mode