CHAPTER 14 PORT FUNCTIONS
User’s Manual U14359EJ4V0UM
490
14.3.11 Port CS
Port CS is an 8-bit I/O port that can be set to the input or output mode in 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
PCS
PCS7
PCS6
PCS5
PCS4
PCS3
PCS2
PCS1
PCS0
FFFFF008H
Undefined
Bit position
Bit name
Function
7 to 0
PCSn
(n = 7 to 0)
Port CS
I/O port
In addition to their function as port pins, in the control mode, the port pins can also operate as the chip select signal
outputs when memory is externally expanded, the row address strobe signal outputs to DRAM, and the read/write
strobe signal output to an external I/O.
(1) Operation in control mode
Port
Alternate Function Pin Name
Remark
Block Type
PCS0
CS0
Chip select signal output
PCS1
CS1/RAS1
Chip select signal output/
row address signal output
J
PCS2
CS2/IOWR
Chip select signal output/
write strobe signal output
K
PCS3
CS3/RAS3
PCS4
CS4/RAS4
Chip select signal output/
row address signal output
J
PCS5
CS5/IORD
Chip select signal output/
read strobe signal output
K
PCS6
CS6/RAS6
Chip select signal output/
row address signal output
Port CS
PCS7
CS7
Chip select signal output
J