UPD78F0537DGA(T)-9EV-A NEC, UPD78F0537DGA(T)-9EV-A Datasheet - Page 512

• 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

interrupt servicing takes place. Before each interrupt request is acknowledged, the EI instruction must always be
issued to enable interrupt request acknowledgment.
than that of INTxx, and multiple interrupt servicing does not take place. The INTyy interrupt request is held pending,
and is acknowledged following execution of one main processing instruction.
512
Example 1. Multiple interrupt servicing occurs twice
During servicing of interrupt INTxx, two interrupt requests, INTyy and INTzz, are acknowledged, and multiple
Example 2. Multiple interrupt servicing does not occur due to priority control
Interrupt request INTyy issued during servicing of interrupt INTxx is not acknowledged because its priority is lower
PR = 0: Higher priority level
PR = 1: Lower priority level
IE = 0:
Interrupt request acknowledgment disabled
INTxx
(PR = 1)
Main processing
EI
Figure 19-10. Examples of Multiple Interrupt Servicing (1/2)
INTxx
(PR = 0)
1 instruction execution
Main processing
IE = 1
IE = 0
EI
CHAPTER 19 INTERRUPT FUNCTIONS
INTyy
(PR = 0)
INTxx servicing
User’s Manual U17260EJ6V0UD
RETI
EI
IE = 1
INTyy
(PR = 1)
IE = 0
IE = 1
INTxx servicing
IE = 0
IE = 1
IE = 0
RETI
INTzz
(PR = 0)
EI
INTyy servicing
RETI
EI
INTyy servicing
RETI
IE = 1
IE = 0
INTzz servicing
RETI