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TMP92CM22
2007-02-16
92CM22-62
3.5.6 Port 8 (P80 to P83)
Port 8 is 4-bit output port. Resetting sets output latch of P82 to “0” and set output
latches of P80, P81, and P83 to “1”.
In addition to functioning as a output port, port 8 can also function as a output chip select
signal (
CS0 to CS3).
These settings operate by programming “1” to the corresponding bit of P8FC.
Resetting set all bits of P8FC to “0”, these pits set output mode.
Figure 3.5.12 Port 8
Port 8 Register
7 6 5 4 3 2 1 0
Bit symbol P83 P82 P81 P80
Read/Write R/W
After reset 1 0 1 1
Port 8 Function Register
7 6 5 4 3 2 1 0
Bit symbol P83F P82F P81F P80F
Read/Write W
After reset 0 0 0 0
Function
0: Port
1:
3CS
0: Port
1:
2CS
0: Port
1:
1CS
0: Port
1:
0CS
Note 1: Read-modify-write instruction is prohibited for the registers P8FC.
Note 2: When set P82 pin as
2CS
after release reset, set function register (P8FC<P82F> = 1) in keep output latch of
P82 to “0” (P8<P82> = 0).
If set function register (P8FC<P82F> = 1) after set output latch to “1” (P8<P82> = 1), maybe operation become
to error because
2CS
output don’t output correctly.
Figure 3.5.13 Register for Port 8
Internal data bus
Reset
Output latch
P8 write
S
A
Selector
B
P8 read
P80 ( CS0 )
P81 (
CS1 )
P82 (
CS2 )
P83 (
CS3 )
Function control
(on bit basis)
P8FC write
CS0 , CS1, CS2 , CS3
P8
(0020H)
P8FC
(0023H)