TMP91C824
91C824-6
2008-02-20
2.3
Pin Names and Functions
The names of the input/output pins and their functions are described below.
Table 2.3.1 Pin Names and Functions (1/3)
Pin Name
Number
of Pins
I/O Functions
D0 to D7
8
I/O
Data (Lower): Bits 0 to 7 of data bus
P10 to P17
D8 to D15
8 I/O
I/O
Port 1: I/O port that allows I/O to be selected at the bit level
(when used to the external 8-bit bus)
Data (Upper): bits 8 to15 of data bus
P20 to P27
A16 to A23
8 Output
Output
Port 2: Output port
Address: Bits 16 to 23 of address bus
A8 to A15
8
Output
Address: Bits 8 to 15 of address bus
A0 to A7
8
Output
Address: Bits 0 to 7 of address bus
RD
1
Output
Read: Strobe signal for reading external memory
RD is outputted by setting PZ<RDE> to “0” even when read internal
memory.
WR
1
Output
Write: Strobe signal for writing data to pins D0 to D7
PZ2
HWR
1 I/O
Output
Port Z2: I/O port (with pull-up resistor)
High write: Strobe signal for writing data to pins D8 to D15
PZ3
R/
W
1 I/O
Output
Port Z3: I/O port (with pull-up resistor)
Read/write: 1 represents read or dummy cycle; 0 represents write cycle.
P54
BUSRQ
1 I/O
Output
Port 54: I/O port (with pull-up resistor)
Bus request: High-impedance used to request bus release
P55
BUSAK
1 I/O
Output
Port 55: I/O port (with pull-up resistor)
Bus acknowledge: Signal used to acknowledge bus release
P56
WAIT
1 I/O
Input
Port 56: I/O port (with pull-up resistor)
Wait: Pin used to request CPU bus wait ((1
+
N) wait states)
P60
CS0
1 Output
Output
Port 60: Output port
Chip select 0: Outputs 0 when address is within specified address area.
P61
CS1
1 Output
Output
Port 61: Output port
Chip select 1: Outputs 0 when address is within specified address area
P62
CS2
CS2A
1 Output
Output
Output
Port 62: Output port
Chip select 2: Outputs 0 when address is within specified address area
Expand chip select 2A: Outputs 0 when address is within specified address
area
P63
CS3
1 Output
Output
Port 63: Output port
Chip select 3: Outputs 0 when address is within specified address area
P64
EA24
CS2B
1
Output
Output
Output
Port 64: Output port
Address 24: Expand address
Expand chip select 2B: Outputs 0 when address is within specified address
area
P65
EA25
CS2C
1 Output
Output
Output
Port 65: Output port
Address 25: Expand address
Expand chip select 2C: Outputs 0 when address is within specified address
area
P66
CS2D
1 Output
Output
Port 66: Output port
Expand chip select 2D: Outputs 0 when address is within specified address
area
P67
CS2E
1 Output
Output
Port 67: Outpt port
Expand chip select 2E: Outputs 0 when address is within specified address
area