sh6620a SinoWealth Micro-Electronics Corp. Ltd, sh6620a Datasheet - Page 10

• Manufacturer Part Number: sh6620a
• Description: Mask 4-bit Microcontroller
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

5. Port Interrupt
PBC interrupt (PORTB & C 8bits, falling edge) is controlled by Port I/O register. Only Input Port has Port Interrupt. Thus, if an
interrupt enable flag IEP is set to 1 & one port bit high goes low been touched and that the condition is the other port bits are high
level.
6. System Clock and Oscillator
System clock generator produces the basic clock pulses that provide the system clock with CPU and peripherals.
Instruction cycle time
(1) 4/32.768KHz ( ≈ 122us) for 32.768KHz system clock.
(2) 4/4MHz ( = 1us) for 4MHz system clock.
Oscillator
(1) Crystal oscillator: 32.768KHz - 4MHz.
(2) Ceramic resonator: 400KHz - 4MHz.
(3) RC oscillator: 400KHz - 4MHz.
(4) External input clock: 30KHz - 4MHz.
OSCO
OSCI
OSCI
OSCO
Fosc/4
32.768K ~ 4MHz
400K ~ 4MHz
V
Ceramic
C1
External clock source
C2
C1
DD
Crystal
C2
R
10
C1, C2 Setting :
Crystal 32.768KHz :
C1, C2 < 56p (
C1, C2 < 56p (
Crystal 4MHz :
C1, C2 < 33p (
C1, C2 < 10p (
C1, C2 Setting :
Ceramic 400KHz :
20p < C1, C2 < 470p (
20p < C1, C2 < 150p (
Ceramic 4MHz :
20p < C1, C2 < 100p (
C1, C2 < 10p (
V
V
V
V
DD
DD
DD
DD
V
DD
= 5V);
= 3V).
= 5V);
= 3V).
= 3V).
V
V
V
DD
DD
DD
= 5V);
= 3V).
= 5V);
SH6620A