UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 125

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

6.1 Functions of Clock Generator
The clock generator generates the clock to be supplied to the CPU and peripheral hardware.
The following system clocks and clock oscillators are selectable.
(1) Main system clock
(2) Subsystem clock
(3) Internal low-speed oscillation clock (clock for watchdog timer)
Remarks 1. f
<1> X1 oscillator
<2> Internal high-speed oscillator
An external main system clock (f
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
• Internal low-speed oscillator
This circuit oscillates at a frequency of f
clock control register (PCC) and clock operation mode select register (OSCCTL). An external subsystem
clock (f
This circuit oscillates a clock of f
oscillation clock always starts operating. Oscillation can be stopped by using the internal oscillator mode
register (RCM).
The internal low-speed oscillation clock cannot be used as the CPU clock. The following hardware operates
with the internal low-speed oscillation clock.
• Watchdog timer
• TMH1 (f
This circuit oscillates a clock of f
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 oscillator mode register (RCM).
2. f
3. f
4. f
5. f
6. f
EXCLKS
RL
X
RH
EXCLK
XT
EXCLKS
RL
:
:
:
, f
:
RL
= 32.768 kHz) can also be supplied from the EXCLKS pin.
: External main system clock frequency
/2
: External subsystem clock frequency
X1 clock oscillation frequency
Internal high-speed oscillation clock frequency
XT1 clock oscillation frequency
Internal low-speed oscillation clock frequency
7
, f
RL
/2
9
)
CHAPTER 6 CLOCK GENERATOR
EXCLK
RL
= 4 to 20 MHz) can also be supplied from the EXCLK pin. As the main
User’s Manual U17554EJ4V0UD
X
RH
= 240 kHz (TYP.). After a RESET release, the internal low-speed
= 4 to 20 MHz. Oscillation can be stopped by executing the STOP
XT
= 8 MHz (TYP.). After a RESET release, the CPU always starts
= 32.768 kHz. Oscillation can be stopped by using the processor
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