UPD78F9222MC(T)-5A4-A NEC, UPD78F9222MC(T)-5A4-A Datasheet - Page 80

• Manufacturer Part Number: UPD78F9222MC(T)-5A4-A
• Description: 8BIT MCU, 4K FLASH, 256B RAM, 78F9222
• Manufacturer: NEC

Specifications of UPD78F9222MC(T)-5A4-A

• Controller Family/series: UPD78
• No. Of I/o's: 17
• Ram Memory Size: 256Byte
• Cpu Speed: 10MHz
• No. Of Timers: 4
• No. Of: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 4KB
• Oscillator Type: External, Internal

(3) External clock input circuit
80
Remark PCC:
• High-speed operation
• Improvement of expandability
If external clock input is selected by the option byte, the following is possible.
Figures 5-12 and 5-13 show the timing chart and status transition diagram of default start by external clock input.
The accuracy of processing is improved as compared with high-speed internal oscillation (8 MHz (TYP.))
because an oscillation frequency of 2 to 10 MHz can be selected and an external clock with a small frequency
deviation can be supplied.
If the external clock input circuit is selected as the oscillator, the X2 pin can be used as an I/O port pin. For
details, refer to CHAPTER 4 PORT FUNCTIONS.
PPCC: Preprocessor clock control register
Figure 5-11. Status Transition of Default Start by Crystal/Ceramic Oscillation
Processor clock control register
Interrupt
HALT
CHAPTER 5 CLOCK GENERATORS
oscillation stabilization
oscillation selected
Clock division ratio
instruction
Crystal/ceramic
power-on-clear
variable during
CPU operation
HALT
Wait for clock
by option byte
User’s Manual U16898EJ5V0UD
Reset by
application
Power
V
Start with PCC = 02H,
PPCC = 02H
instruction
DD
STOP
> 2.1 V (TYP.)
STOP
Interrupt
Reset signal