CHAPTER 14 PORT FUNCTIONS
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User’s Manual U14492EJ3V0UD
14.3.10 Port CM
Port CM is a 5-bit I/O port in which input or output can be specified in 1-bit units.
7
–
PCM
6
–
5
–
4
PCM4
3
PCM3
2
PCM2
1
PCM1
0
PCM0
Address
FFFFF00CH
Initial value
Undefined
Bit Position
Bit Name
Function
4 to 0
PCMn
(n = 4 to 0)
I/O port
Besides functioning as a port, in control mode, this can operate as the wait insertion signal input, internal system
clock output, and bus hold control signal output.
(1) Operation in control mode
Port
Alternate Pin Name
Remarks
Block Type
PCM0
WAIT
Wait insertion signal input
D
PCM1
CLKOUT
Internal system clock output
J
PCM2
HLDAK
Bus hold acknowledge signal output
J
PCM3
HLDRQ
Bus hold request signal input
D
Port CM
PCM4
−
Fixed in port mode
E
(2) Setting in I/O mode and control mode
Port CM is set in I/O mode using the port CM mode register (PMCM). In control mode, it is set using the port
CM mode control register (PMCCM).
(a) Port CM mode register (PMCM)
This register can be read/written in 8-bit or 1-bit units.
7
1
PMCM
6
1
5
1
4
PMCM4
3
PMCM3
2
PMCM2
1
PMCM1
0
PMCM0
Address
FFFFF02CH
Initial value
FFH
Bit Position
Bit Name
Function
4 to 0
PMCMn
(n = 4 to 0)
Specifies input/output mode of PCMn pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)