upd7566a Renesas Electronics Corporation., upd7566a Datasheet - Page 20

• Manufacturer Part Number: upd7566a
• Description: 4-bit Single-chip Microcomputer
• Manufacturer: Renesas Electronics Corporation.

20
2.10
(1, 2, and 3), and a multiplexer. This circuit inputs the output from the system clock generator (i.e., CL). An event
pulse (from pin P00) selects a clock source and prescaler, as specified by the clock mode register, and supplies a
count pulse (CP) to the timer/event counter.
Note indicates that an instruction has been executed.
Caution When setting a code in the clock mode register by the OPL instruction, be sure to clear the bit 0 (which
The clock control circuit consists of a 2-bit clock mode register (made up of bits CM2 and 1), three prescalers
A code is set in the clock mode register by an OPL (L = 12) instruction.
CLOCK CONTROL CIRCUIT
corresponds to CM0 of EVAKIT-7500B ( PD7500) during emulation) for the accumulator to 0.
P
CL
00
PRESCALER 1
(1/4)
CM2 CM1
CM2
Fig. 2-11 Clock Mode Register Format
CM1
Fig. 2-10 Clock Control Circuit
OPL
Note
CM2 CM1
0
0
1
1
Clock mode register
Internal Bus
0
1
0
1
Count pulse frequency (CP)
CL x 1/256
P00
CL x 1/32
CL x 1/4
PRESCALER 2
(1/8)
CP
PRESCALER 3
(1/8)
PD7566A, 7566A(A)