PSD834F4A-20UI View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
PSD834F4A-20UI Datasheet PDF : 128 Pages
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MCU bus interface
PSD8XXFX
15.5
80C31
Figure 20 shows the bus interface for the 80C31, which has an 8-bit multiplexed
address/data bus. The lower address byte is multiplexed with the data bus. The MCU control
signals Program Select Enable (PSEN, CNTL2), Read Strobe (RD, CNTL1), and Write
Strobe (WR, CNTL0) may be used for accessing the internal memory and I/O ports blocks.
Address Strobe (ALE/AS, PD0) latches the address.
Figure 20. Interfacing the PSD with an 80C31
AD7-AD0
AD[ 7:0]
RESET
RESET
Obsolete
80C31
31
EA/VP
19 X1
18 X2
9 RESET
12
13
INT0
14
15
INT1
T0
T1
1
2 P1.0
3
4
5
6
P1.1
P1.2
P1.3
P1.4
7
P1.5
P1.6
8 P1.7
39
P0.0
P0.1
38
37
P0.2
P0.3
P0.4
36
35
P0.5
P0.6
P0.7
34
33
32
P2.0 21
P2.1 22
P2.2 23
P2.3 24
P2.4 25
P2.5
P2.6
P2.7
26
27
28
17
RD
WR 16
PSEN 29
30
ALE/P
11
TXD
RXD 10
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
A8
A9
A10
A11
A12
A13
A14
A15
RD
WR
PSEN
ALE
ProducRtES(ETs) -
PSD
AD0
AD1
AD2
) AD3
AD4
t(s AD5
AD6
Obsolete Produc AD7
30
31
ADIO0
ADIO1
32
33
34
ADIO2
ADIO3
35 ADIO4
36
37
ADIO5
ADIO6
ADIO7
39 ADIO8
40
41
42
ADIO9
ADIO10
ADIO11
43 ADIO12
44 ADIO13
45
46
ADIO14
ADIO15
47 CNTL0 (WR)
50 CNTL1(RD)
49 CNTL2 (PSEN)
10 PD0-ALE
9 PD1
8 PD2
PA0
29
28
PA1 27
PA2
PA3
PA4
25
24
23
PA5
PA6
PA7
22
21
PB0
7
6
PB1
PB2
5
PB3
PB4
4
3
2
PB5
PB6
52
PB7 51
PC0
PC1
PC2
PC3
PC4
PC5
PC6
PC7
20
19
18
17
14
13
12
11
48
RESET
AI02880C
62/128
Doc ID 7833 Rev 7
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