UPD75218 NEC, UPD75218 Datasheet - Page 16

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UPD75218

Manufacturer Part Number
UPD75218
Description
4-BIT SINGLE-CHIP MICROCOMPUTER
Manufacturer
NEC
Datasheet
16
5.2
register (SCC).
Note
Remarks 1. f
Operation of the clock generator is specified by the processor clock control register (PCC) and system clock control
The main system clock or subsystem clock can be selected.
The instruction execution time is variable.
0.67 s, 1.33 s, 10.7 s (main system clock: 6.0 MHz)
0.95 s, 1.91 s, 15.3 s (main system clock: 4.19 MHz)
122 s (subsystem clock: 32.768 kHz)
CLOCK GENERATOR
Instruction execution
HALT
STOP
2. f
3. f
4.
5. PCC: Processor clock control register
6. SCC: System clock control register
7. 1 clock cycle (t
4
Chapter 12.
X
XT
XX
Note
Note
= CPU clock
= Main system clock frequency
= Subsystem clock frequency
= System clock frequency
PCC2 and
PCC3
clear
SCC3
SCC0
PCC0
PCC1
PCC2
PCC3
SCC
PCC
XT1
XT2
X2
X1
Subsystem
clock generator
Main system
clock generator
CY
) of
Oscillation
stop
STOP F/F
is 1 machine cycle of an instruction. For t
Fig. 5-1 Clock Generator Block Diagram
Q
f
f
X
XT
R
S
Watch timer
Timer/pulse
generator
f
XX
1/2 1/6
Frequency divider
1/8 to 1/4096
HALT F/F
S
R
CY
, see ”AC Characteristics“ in
Q
• FIP controller
• Basic interval timer (BT)
• Timer/event counter
• Serial interface
• Watch timer
• INT0 noise eliminator
Wait release signal from BT
RES signal (internal reset)
Standby release signal from
interrupt control circuit
• CPU
• INT0 noise eliminator
• INT1 noise eliminator
Frequency
divider
1/4
PD75218

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