PSD834F4A-20UI View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

PSD834F4A-20UI

Flash in-system programmable (ISP) ipherals for 8-bit MCUs, 5 V

STMicroelectronics 

MCU bus interface

PSD8XXFX

Figure 22. Interfacing the PSD with the 80C251, with RD and PSEN inputs

80C251SB

PSD

uct(s) RESET

2

3

4

5

P1.0

P1.1

P1.2

P1.3

6

7

8

P1.4

P1.5

9

P1.6

P1.7

21

X1

20 X2

11

13

P3.0/RXD

14 P3.1/TXD

P3.2/INT0

15 P3.3/INT1

16 P3.4/T0

17 P3.5/T1

10 RST

35

EA

P0.0

P0.1

43

42

P0.2 41

P0.3 40

P0.4 39

P0.5 38

P0.6 37

P0.7 36

P2.0 24

P2.1 25

P2.2 26

P2.3 27

P2.4 28

P2.5 29

P2.6 30

P2.7 31

ALE 33

32

PSEN

18

WR 19

RD/A16

A0

A1

A2

A3

A4

A5

A6

A7

AD8

AD9

AD10

AD11

AD12

AD13

AD14

AD15

ALE

RD

WR

PSEN

te Prod RESET

RESET

A0

A1

A2

A3

A4

A5

A6

A7

AD8

AD9

AD10

AD11

AD12

AD13

AD14

AD15

30

31

ADIO0

ADIO1

32 ADIO2

33 ADIO3

34 ADIO4

35 ADIO5

36

37

ADIO6

ADIO7

39

40

ADIO8

ADIO9

41 ADIO10

42

43

44

ADIO11

ADIO12

ADIO13

45 ADIO14

46 ADIO15

47 CNTL0 (WR)

50 CNTL1(RD)

49 CNTL 2(PSEN)

10

9

8

PD0- ALE

PD1

PD2

48

RESET

29

PA0

PA1

PA2

28

27

PA3

PA4

PA5

25

24

23

PA6 22

PA7 21

7

PB0 6

PB1 5

PB2

PB3

PB4

4

3

PB5

PB6

2

52

PB7 51

PC0

PC1

20

19

PC2

PC3

PC4

PC5

PC6

PC7

18

17

14

13

12

11

sole AI02882C

Ob Table 19. 80C251 configurations

t(s) - Configuration

80C251 READ/WRITE

pins

c WR

du 1

RD

roPSEN

P WR

2

te PSEN only

le WR

3

o PSEN only

bs WR

O4

RD

Connecting to PSD pins

Page mode

CNTL0

CNTL1

CNTL2

CNTL0

CNTL1

CNTL0

CNTL1

CNTL0

CNTL1

Non-Page mode, 80C31 compatible

A7-A0 multiplex with D7-D0

Non-Page mode

A7-A0 multiplex with D7-D0

Page mode

A15-A8 multiplex with D7-D0

Page mode

A15-A8 multiplex with D7-D0

PSEN

CNTL2

64/128

Doc ID 7833 Rev 7

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