R5F21191SP#U0 Renesas Electronics America, R5F21191SP#U0 Datasheet - Page 269

• Manufacturer Part Number: R5F21191SP#U0
• Description: IC R8C MCU FLASH 8K 20SSOP
• Manufacturer: Renesas Electronics America
• Series: M16C™ M16C/R8C/Tiny/19r

Specifications of R5F21191SP#U0

• Core Processor: R8C
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: SIO, UART/USART
• Peripherals: LED, POR, Voltage Detect, WDT
• Number Of I /o: 13
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Ram Size: 384 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 4x1b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 20-SSOP
• For Use With: R0K521134S000BE - KIT EVAL STARTER FOR R8C/13R0E521174CPE10 - EMULATOR COMPACT R8C/18/19/1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

Rev.2.00 Oct 17, 2005
REJ09B0001-0200
5.2 Interrupt Control
Chapter 5
This section explains how to enable/disable maskable interrupts and set acknowledge priority. The expla-
nation here does not apply to non-maskable interrupts.
Maskable interrupts are enabled and disabled by using the I flag, IPL, and bits ILVL2 to ILVL0 in each
interrupt control register. Whether or not an interrupt is requested is indicated by the IR bit in each interrupt
control register.
For details about the memory allocation and the configuration of interrupt control registers, refer to the
R8C’s hardware manual.
Figure 5.2.1 Timing with Which Changes of I Flag are Reflected in Interrupt Handling
5.2.1 I Flag
5.2.2 IR Bit
When changed by REIT instruction
When changed by FCLR, FSET, POPC, or LDC instruction
The I flag is used to disable/enable maskable interrupts. When the I flag is set to 1 (enabled), all
maskable interrupts are enabled; when the I flag is cleared to 0 (disabled), they are disabled.
When the I flag is changed, the altered flag status is reflected in determining whether or not to accept an
interrupt request with the following timing:
The IR bit is set to 1 (interrupt requested) when an interrupt request is generated. The IR bit is cleared to
0 (interrupt not requested) after the interrupt request is acknowledged and the program branches to the
corresponding interrupt vector.
The IR bit can be cleared to 0 by a program. Do not set it to 1.
• If the flag is changed by an REIT instruction, the changed status takes effect beginning with the
• If the flag is changed by an FCLR, FSET, POPC, or LDC instruction, the changed status takes
REIT instruction.
effect beginning with the next instruction.
Interrupt request generated
Interrupts
Interrupt request generated
page 249 of 263
Previous
instruction
(If I flag is changed from 0 to 1 by REIT instruction)
Previous
instruction
(If I flag is changed from 0 to 1 by FSET instruction)
Determination whether or not to
accept interrupt request
FSET I
REIT
Interrupt sequence
Next instruction
Determination whether or not to
accept interrupt request
Interrupt sequence
Ti m e
Ti m e
5.2 Interrupt Control