R5F21294SNSP#U0 Renesas Electronics America, R5F21294SNSP#U0 Datasheet - Page 437

• Manufacturer Part Number: R5F21294SNSP#U0
• Description: MCU 3/5V 16K+2K 20PIN-SSOP
• Manufacturer: Renesas Electronics America
• Series: M16C™ M16C/R8C/Tiny/29r

Specifications of R5F21294SNSP#U0

• Core Processor: R8C
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: I²C, LIN, SIO, SSU, UART/USART
• Peripherals: LED, POR, Voltage Detect, WDT
• Number Of I /o: 13
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.2 V ~ 5.5 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

R8C/28 Group, R8C/29 Group
Rev.2.10
REJ09B0279-0210
21.2.5
Sample programs 1 to 3 are for preventing the I flag from being set to 1 (interrupts enabled) before the interrupt
control register is changed for reasons of the internal bus or the instruction queue buffer.
Example 1:
Example 2:
Example 3:
(a) The contents of an interrupt control register can only be changed while no interrupt requests
(b) When changing the contents of an interrupt control register after disabling interrupts, be careful to
(c) When disabling interrupts using the I flag, set the I flag as shown in the sample programs below. Refer
INT_SWITCH1:
INT_SWITCH2:
INT_SWITCH3:
Sep 26, 2008
Changing Interrupt Control Register Contents
corresponding to that register are generated. If interrupt requests may be generated, disable interrupts
before changing the interrupt control register contents.
choose appropriate instructions.
Changing any bit other than IR bit
If an interrupt request corresponding to a register is generated while executing the instruction, the IR bit
may not be set to 1 (interrupt requested), and the interrupt request may be ignored. If this causes a
problem, use the following instructions to change the register: AND, OR, BCLR, BSET
Changing IR bit
If the IR bit is set to 0 (interrupt not requested), it may not be set to 0 depending on the instruction used.
Therefore, use the MOV instruction to set the IR bit to 0.
to (b) regarding changing the contents of interrupt control registers by the sample programs.
FCLR
AND.B
NOP
NOP
FSET
FCLR
AND.B
MOV.W MEM,R0
FSET
PUSHC FLG
FCLR
AND.B
POPC
Use NOP instructions to prevent I flag from being set to 1 before interrupt control register
is changed
Use dummy read to delay FSET instruction
Use POPC instruction to change I flag
I
I
I
#00H,0056H
I
#00H,0056H
I
#00H,0056H
FLG
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; Disable interrupts
;
; Enable interrupts
; Disable interrupts
; Dummy read
; Enable interrupts
; Disable interrupts
; Enable interrupts
; Set TRAIC register to 00h
; Set TRAIC register to 00h
; Set TRAIC register to 00h
21. Usage Notes