DS80C310

4 of 23

DIP

PLCC

TQFP

SIGNAL

NAME

DESCRIPTION

1

2

3

4

5

6

7

8

2

3

4

5

6

7

8

9

40

41

42

43

44

1

2

3

Port

Alternate Function

P1.0

T2

External I/O for Timer/Counter 2

P1.1

T2EX

Timer/Counter 2 Capture/Reload Trigger

P1.2

none

(DS80C320 has a serial port RXD)

P1.3

none

(DS80C320 has a serial port TXD)

P1.4

INT2

External Interrupt 2 (Positive Edge Detect)

P1.5

INT3

External Interrupt 3 (Negative Edge Detect)

P1.6

INT4

External Interrupt 4 (Positive Edge Detect)

P1.7

INT5

External Interrupt 5 (Negative Edge Detect)

21

22

23

24

25

26

27

28

24

25

26

27

28

29

30

31

18

19

20

21

22

23

24

25

A8 (P2.0)

A9 (P2.1)

A10(P2.2)

A11(P2.3)

A12(P2.4)

A13 P2.5)

A14(P2.6)

A15(P2.7)

A8-15 (Port 2) -Output. Port 2 serves as the MSB for external

addressing. P2.7 is A15 and P2.0 is A8. The DS80C310 will

automatically place the MSB of an address on P2 for external

ROM and RAM access. Although Port 2 can be accessed like

an ordinary I/O port, the value stored on the Port 2 latch will

never be seen on the pins (due to memory access). Therefore

writing to Port 2 in software is only useful for the instructions

MOVX A, @ Ri or MOVX @ Ri, A. These instructions use the

Port 2 internal latch to supply the external address MSB; the

Port 2 latch value will be supplied as the address information.

10-17

10

11

12

13

14

15

16

17

11,

13-19

11

13

14

15

16

17

18

19

5,7-13

5

7

8

9

10

11

12

13

P3.0-3.7

Port 3 - I/O. Port 3 functions as both an 8-bit bidirectional I/O

port and an alternate functional interface for external Interrupts,

reset condition of Port 3 is with all bits at a logic 1. In this

state, a weak pullup holds the port high. This condition also

serves as an input mode, since any external circuit that writes

to the port will overcome the weak pullup. When software

writes a 0 to any port pin, the DS80C310 will activate a strong

pulldown that remains on until either a 1 is written or a reset

occurs. Writing a 1 after the port has been at 0 will cause a

strong transition driver to turn on, followed by a weaker

sustaining pullup. Once the momentary strong driver turns off,

the port once again becomes both the output high and input

state. The alternate modes of Port 3 are outlined below.

Port

Alternate

Mode

P3.0

RXD0

Serial Port 0 Input

P3.1

TXD0

Serial Port 0 Output

P3.2

INT0

External Interrupt 0

P3.3

INT1

External Interrupt 1

P3.4

T0

Timer 0 External Input

P3.5

T1

Timer 1 External Input

P3.6

WR

External Data Memory Write Strobe

P3.7

RD

External Data Memory Read Strobe

31

35

29

EA

Input. This pin must be connected to ground for proper

operation.

-

12

34

6

28

NC

NC - Reserved. These pins should not be connected. They

are reserved for use with future devices in this family.