UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 58

no-image

UPD75238GJ

Manufacturer Part Number
UPD75238GJ
Description
4 BIT SINGLE-CHIP MICROCOMPUTER
Manufacturer
NEC [NEC]
Datasheet
58
4.3 CLOCK OUTPUT CIRCUIT
(1) Configuration of the clock output circuit
(2) Functions of the clock output circuit
Fig. 4-20 shows the configuration of the clock output circuit.
The clock output circuit outputs a clock pulse signal on the P22/PCL pin for remote control or for supplying
clock pulses to a peripheral LSI device.
The procedure for outputting a clock pulse signal is as follows:
Remark The clock output circuit is designed so that pulses with short widths do not appear in enabling
(a) Select a clock output frequency, and disable clock output.
(b) Write a 0 in the P22 output latch.
(c) Set the output mode for port 2.
(d) Enable clock output.
From the clock
generator
f
f
f
or disabling clock output.
X
X
X
CLOM3
/2
/2
/2
3
4
6
0
4
Fig. 4-20 Configuration of the Clock Output Circuit
CLOM1
Selector
CLOM0
CLOM
Internal bus
P22 output
latch
PORT2.2
Output
buffer
Port 2 input/
output mode
specification bit
Bit 2 of PMGB
PCL/P22
PD75238

Related parts for UPD75238GJ