UPD78F0034BGC-8BS-A Renesas Electronics America, UPD78F0034BGC-8BS-A Datasheet - Page 419

• Manufacturer Part Number: UPD78F0034BGC-8BS-A
• Description: MCU 8-Bit 78K0 CISC 32KB Flash 2.5V/3.3V/5V 64-Pin LQFP
• Manufacturer: Renesas Electronics America

Specifications of UPD78F0034BGC-8BS-A

• Package: 64LQFP
• Family Name: 78K0
• Maximum Speed: 12 MHz
• Ram Size: 1 KB
• Program Memory Size: 32 KB
• Operating Supply Voltage: 2.5|3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 51
• Interface Type: 3-Wire/UART
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

Example 1. Nesting occurs twice
place. Before each interrupt request is acknowledged, the EI instruction must always be issued to enable interrupt
request acknowledgment.
Example 2. Nesting does not occur due to priority control
than that of INTxx, and nesting does not take place. The INTyy interrupt request is held pending, and is acknowledged
following execution of one main processing instruction.
During servicing of interrupt INTxx, two interrupt requests, INTyy and INTzz, are acknowledged, and nesting takes
Interrupt request INTyy issued during servicing of interrupt INTxx is not acknowledged because its priority is lower
PR = 0:
PR = 1:
IE = 0:
Higher priority level
Lower priority level
Interrupt request acknowledgment disabled
INTxx
(PR = 1)
Main processing
EI
INTxx
(PR = 0)
1 instruction execution
Main processing
IE = 1
IE = 0
EI
INTyy
(PR = 0)
Figure 19-13. Nesting Examples (1/2)
CHAPTER 19 INTERRUPT FUNCTIONS
INTxx servicing
User’s Manual U14046EJ5V0UD
RETI
EI
INTyy
(PR = 1)
IE = 0
IE = 1
IE = 1
IE = 0
INTxx servicing
IE = 1
IE = 0
RETI
INTzz
(PR = 0)
EI
INTyy servicing
RETI
EI
INTyy servicing
RETI
IE = 1
IE = 0
INTzz servicing
RETI
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