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¡ Semiconductor

MSM82C54-2RS/GS/JS

• Select Counter (SC0, SC1):

Selection of set counter

0

1

1

0

SC1

Set Contents

1

0

1

0

SC0

Counter #0 selection

Counter #1 selection

Counter #2 selection

Read Back Command

• Read/Load (RL1, RL0):

Count value Reading/Loading format setting

0

1

1

0

RL1

Set Contents

1

0

1

0

RL0

Counter Latch Operation

Reading/Loading of Least Significant Byte (LSB)

Reading/Loading of Most Significant Byte (MSB)

Reading/Loading of LSB followed by MSB

• Mode (M2, M1, M0):

Operation waveform mode setting

• BCD:

Operation count mode setting

After setting Read/Load, Mode and BCD in each counter as outlined above, next set the desired

count value. (In some Modes, the count value is set first. In next clock, loading is performed,

then counting starts.) This count value setting must conform with the Read/Load format set

in advance. Note that the internal counters are reset to 0000H during control word setting. The

counter value (0000H) can’t be read.

The program sequence of the MSM82C54-2 is flexible.

Free sequence programming is possible as long as the two following rules are observed:

(i) Write the control word before writing the initial count value in each counter.

(ii) Write the initial count value according to the count value read/write format specified by the

control word.

Note: Unlike the MSM82C53-2, the MSM82C54-2 allows count value setting for another

counter between LSB and MSB settings.

0

¥

¥

0

M2

Set Contents

0

1

1

0

M1

1

0

1

0

M0

1

1

0

0

0

1

Mode 0 (Interruput on Terminal Count)

Mode 1 (Programmable One-Shot)

Mode 2 (Rate Generator)

Mode 3 (Square Wave Generator)

Mode 4 (Software Triggered Strobe)

Mode 5 (Hardware Triggered Strobe)

¥: denotes "not specified"

1

0

BCD

Set Contents

Binary Count (16-bit Binary)

BCD Count (4-decade Binary Coded Decimal)