PSD301-B-15J STMICROELECTRONICS [STMicroelectronics], PSD301-B-15J Datasheet - Page 20

• Manufacturer Part Number: PSD301-B-15J
• Description: Low Cost Field Programmable Microcontroller Peripherals
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

10.0
I/O Port
Functions
(
cont.)
Figure 5A. Port A Pin Structure
10.2.2 Port A (PA0-PA7) in Non-Multiplexed Address/Data Mode
In this mode, Port A becomes the low-order data bus byte of the chip. When reading an
internal location, data is presented on Port A pins to the MCU. When writing to an internal
location, data present on Port A pins from the MCU is written to the desired location.
Figure 5B. Port A Track Mode
NOTE: 1. CMOS/OD determines whether the output is open drain or CMOS.
NOTE: 1. The expression for CSADOUT2 must include the following write operation cycle signals:
WR or R / W
RD /E
ALE or AS
AD8 – AD15
A16 – A19
RESET
N
R
N
D
D
R
D
U
D
D
T
E
A
L
A
A
T
A
B
S
A
0
A
7
I
/
/
For CRRWR = 0, CSADOUT2 must include WR = 0.
For CRRWR = 1, CSADOUT2 must include E = 1 and R/W = 0.
AD0 –AD7
WRITE DATA
WRITE DIR
ALE
LATCH
READ DATA
CONTROL
DECODER
READ DIR
A11 – A15
CK
CK
G
D
D
D
LATCH
DFF
DIR
FF
R
R
R
INTERNAL
PAD
ADDR OUT
LATCHED
READ
ADn/ Dn
INTERNAL
CSADIN
MCU
OUT
ALE
I/O
CSADOUT1
CSADOUT2
MUX
READ PIN
(1)
CONTROL
CMOS/ OD
(1)
ENABLE
O
PORT A PIN
I
PSD3XX Family
PA0 – PA7
17