Toshiba TLCS-900 Computer Hardware User Manual


 
TMP92CM22
2007-02-16
92CM22-56
3.5.3 Port 5 (P50 to P57)
Port 5 is an 8-bit general-purpose I/O port*. Bits can be individually set as either inputs
or outputs by control register P5CR and function register P5FC*.
In addition to functioning as a general-purpose I/O port, port 5 can also function as an
address bus (A8 to A15).
After released reset, device set port 5 to pins of follow function by combination of AM1
and AM0 pins.
AM1 AM0 Function Setting after Reset
0 0 Don’t use this setting
0 1 Address bus (A8 to A15)
1 0 Address bus (A8 to A15)
1 1 Don’t use this setting
*: When these ports are used as general-purpose I/O port, each bit can be set individually for input or output. However, each
bit cannot be set individually for input or output even if 1bit or more bits are used as address bus in same port.
All of general-purpose I/O ports except for port that used as address bus are operated as output port.
Please be careful when using this setting.
Figure 3.5.5 Port 5
Internal data bus
Direction control
(on bit basis)*
Reset
P5CR write
Output latch
P5 write
S
B
Selector
A
P5 read
Port 5
P50 to P57
(A8 to A15)
Function control
(on bit basis)
P5FC write
Output buffer
Internal address bus
A
8 to A15