psd311-b-90ui STMicroelectronics, psd311-b-90ui Datasheet - Page 48

• Manufacturer Part Number: psd311-b-90ui
• Description: Low Cost Field Programmable Microcontroller Peripherals
• Manufacturer: STMicroelectronics

Figure 21. Timing of 8-Bit Multiplexed Address/Data Bus Using RD, WR (PSD3X2/3X3)
RD/E/DS as RD
Multiplexed
PAD Input
PA0-PA7 Pins
See referenced notes on page 64
BHE/PSEN
Active High
RW as WR
as Address
Active Low
WR/V
Inputs
as I/O Pin
as I/O Pin
as PSEN
PA0-PA7
PB0-PB7
Direct
A0/AD0-
CSI/A19
A7/AD7
Outputs
as CSI
Any of
Any of
Any of
PP
ALE
ALE
(1)
(2)
or
1
23
2
ADDRESS A
5
3
STABLE INPUT
7
6
6
4
ADDRESS A
READ CYCLE
8
18
12
INPUT
INPUT
DATA VALID
9
32
19
10
13
23
1
2
ADDRESS B
STABLE INPUT
11
36
14
WRITE CYCLE
3
15
14
ADDRESS B
16
32
32
12A
17
13
20
DATA
PSD3XX Family
IN
OUTPUT
OUTPUT
45