Rev. A - Mar. 19, 1999

39

Preliminary

TS80C31X2

For timing purposes as port pin is no longer floating when a 100 mV change from load voltage occurs and begins

7.4.13 Clock Waveforms

Valid in normal clock mode. In X2 mode XTAL2 signal must be changed to XTAL2 divided by two.

Figure 20. Clock Waveforms

This diagram indicates when signals are clocked internally. The time it takes the signals to propagate to the pins,

however, ranges from 25 to 125 ns. This propagation delay is dependent on variables such as temperature and pin

RD and WR propagation delays are approximately 50ns. The other signals are typically 85 ns. Propagation delays

are incorporated in the AC specifications.

CLOCK

XTAL2

ALE

INTERNAL

STATE4

STATE5

STATE6

STATE1

STATE2

STATE3

STATE4

STATE5

EXTERNAL PROGRAM MEMORY FETCH

READ CYCLE

WRITE CYCLE

SERIAL PORT SHIFT CLOCK

PORT OPERATION

PSEN

P0

P2 (EXT)

RD

P0

P2

P0

P2

WR

TXD (MODE 0)

RXD SAMPLED

RXD SAMPLED

P0 PINS SAMPLED

P1, P2, P3 PINS SAMPLED

P1, P2, P3 PINS SAMPLED

P0 PINS SAMPLED

MOV DEST PORT (P1, P2, P3)

(INCLUDES INT0, INT1, TO, T1)

MOV DEST P0

OLD DATA

NEW DATA

DPL OR Rt OUT

DATA OUT

PCL OUT (EVEN IF PROGRAM

MEMORY IS INTERNAL)

PCL OUT (IF PROGRAM

MEMORY IS EXTERNAL)

INDICATES DPH OR P2 SFR TO PCH TRANSITION

DPL OR Rt OUT

FLOAT

PCL OUT (IF PROGRAM

MEMORY IS EXTERNAL)

INDICATES DPH OR P2 SFR TO PCH TRANSITION

INDICATES ADDRESS TRANSITIONS

FLOAT

FLOAT

FLOAT

PCL OUT

PCL OUT

PCL OUT

DATA

SAMPLED

DATA

SAMPLED

DATA

SAMPLED

THESE SIGNALS ARE NOT ACTIVATED DURING THE

EXECUTION OF A MOVX INSTRUCTION

P1

P2

P1

P2

P1

P2

P1

P2

P1

P2

P1

P2

P1

P2

P1

P2