CHAPTER 14 PORT FUNCTIONS
User’s Manual U14359EJ4V0UM
494
14.3.12 Port CT
Port CT is a 6-bit I/O port that can be set to input or output mode in 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
PCT
PCT7
PCT6
PCT5
PCT4
–
–
PCT1
PCT0
FFFFF00AH Undefined
Bit position
Bit name
Function
7 to 4, 1, 0
PCTn
(n = 7 to 4, 1, 0)
Port CT
I/O port
In addition to their function as port pins, in the control mode, the port CT pins operate as control signal outputs for
when the memory is externally expanded.
(1) Operation in control mode
Port
Alternate Function Pin Name
Remark
Block Type
PCT0
LCAS/LWR/LDQM
Column address signal output/
write strobe signal output/
output disable/write mask signal
PCT1
UCAS/UWR/UDQM
Column address signal output/
write strobe signal output/
output disable/write mask signal
PCT4
RD
Read strobe signal output
PCT5
WE
Write enable signal output
PCT6
OE
Output enable signal output
Port CT
PCT7
BCYST
Bus cycle status signal output
J
(2) I/O mode/control mode setting
The port CT I/O mode setting is performed by the port CT mode register (PMCT), and the control mode
setting is performed by the port CT mode control register (PMCCT).
(a) Port CT mode register (PMCT)
This register can be read/written in 8-bit or 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
PMCT
PMCT7
PMCT6
PMCT5
PMCT4
1
1
PMCT1
PMCT0
FFFFF02AH
FFH
Bit position
Bit name
Function
7 to 4, 1, 0
PMCTn
(n = 7 to 4, 1, 0)
Port Mode
Specifies input/output mode for PCTn pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)