PSD3XX Family
10.
I/O Port
Functions
(cont.)
10.3.2 Port B (PB0-PB7) in 16-bit Multiplexed Address/Data Mode
In this mode, Port B becomes the low-order data bus byte to the MCU chip. When reading
an internal high-order location, data is presented on Port B pins to the MCU. When writing
to an internal high-order location, data present on Port B pins from the MCU is written to the
desired location.
Figure 6. Port B Pin Structure
READ PIN
I
I
N
N
T
T
READ DATA
E
E
R
R
CMOS/OD (1)
N
N
MCU
A
A WRITE DATA
L
L
CK
t(s) C
D
S
A
O
T
c U
A
u T
DFF
DR
d B
ro ) B
U
P t(s U
S
S
lete uc D
d C
8
so ro S
•
READ DIR
0
•
b P •
•
- O te •
D
•
1
) le 7
5
WRITE DIR
D
DIR
CK FF
R
t(s o RESET
I/O
OUT
Dn
MUX
CSn
CONTROL
PORT B PIN
ENABLE
OObbssoolleettee PPrroodduucct(s) - Obs NOTE: 1. CMOS/OD determines whether the output is open drain or CMOS.
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