6 port 8 (p80 to p83) – Toshiba H1 SERIES TLCS-900 User Manual
Page 64

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:
3
CS
0: Port
1:
2
CS
0: Port
1:
1
CS
0: Port
1:
0
CS
Note 1: Read-modify-write instruction is prohibited for the registers P8FC.
Note 2: When set P82 pin as
2
CS
after release reset, set function register (P8FC
= 1) in keep output latch of
P82 to “0” (P8
= 0).
If set function register (P8FC
= 1) after set output latch to “1” (P8
to error because
2
CS
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)