UPD78F0537DGA(T)-9EV-A NEC, UPD78F0537DGA(T)-9EV-A Datasheet - Page 140

• Manufacturer Part Number: UPD78F0537DGA(T)-9EV-A
• Description: 8BIT MCU, 128K FLASH, 7KB RAM, SMD
• Manufacturer: NEC

Specifications of UPD78F0537DGA(T)-9EV-A

• Controller Family/series: UPD78
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 8
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

6.1 Functions of Clock Generator
140
The clock generator generates the clock to be supplied to the CPU and peripheral hardware.
The following three kinds of system clocks and clock oscillators are selectable.
(1) Main system clock
(2) Subsystem clock
Remarks 1. f
<1> X1 oscillator
<2> Internal high-speed oscillator
An external main system clock (f
external main system clock input can be disabled by executing the STOP instruction or using RCM.
As the main system clock, a high-speed system clock (X1 clock or external main system clock) or internal high-
speed oscillation clock can be selected by using the main clock mode register (MCM).
• Subsystem clock oscillator
An external subsystem clock (f
external subsystem clock input can be disabled by setting PCC and OSCCTL.
This circuit oscillates at a frequency of f
and XT2.
operation mode select register (OSCCTL).
This circuit oscillates a clock of f
Oscillation can be stopped by executing the STOP instruction or using the main OSC control register
(MOC).
This circuit oscillates a clock of f
operating with this internal high-speed oscillation clock. Oscillation can be stopped by executing the
STOP instruction or using the internal oscillation mode register (RCM).
2. f
3. f
4. f
5. f
X
RH
EXCLK
XT
EXCLKS
:
:
:
Oscillation can be stopped by using the processor clock control register (PCC) and clock
:
: External subsystem clock frequency
Internal high-speed oscillation clock frequency
X1 clock oscillation frequency
External main system clock frequency
XT1 clock oscillation frequency
CHAPTER 6 CLOCK GENERATOR
EXCLKS
EXCLK
= 32.768 kHz) can also be supplied from the EXCLKS/XT2/P124 pin. An
X
= 1 to 20 MHz) can also be supplied from the EXCLK/X2/P122 pin. An
User’s Manual U17260EJ6V0UD
= 1 to 20 MHz by connecting a resonator to X1 and X2.
RH
XT
= 8 MHz (TYP.). After a reset release, the CPU always starts
= 32.768 kHz by connecting a 32.768 kHz resonator across XT1