R5F21256SNFP#U0 Renesas Electronics America, R5F21256SNFP#U0 Datasheet - Page 479

• Manufacturer Part Number: R5F21256SNFP#U0
• Description: IC R8C MCU FLASH 32K 52LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/2x/25r

Specifications of R5F21256SNFP#U0

• Core Processor: R8C
• Core Size: 16/32-Bit
• Speed: 20MHz
• Connectivity: I²C, LIN, SIO, SSU, UART/USART
• Peripherals: POR, Voltage Detect, WDT
• Number Of I /o: 41
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 52-LQFP
• For Use With: R0K521256S000BE - KIT EVAL STARTER FOR R8C/25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

R8C/24 Group, R8C/25 Group
Rev.3.00
REJ09B0244-0300
Figure 21.2
21.3.2.2
The following three workarounds should be performed in programmable waveform generation mode.
(1) To write to registers TRBPRE and TRBPR during count operation (TCSTF bit is set to 1), note the
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(2) To change registers TRBPRE and TRBPR during count operation (TCSTF bit is set to 1), synchronize
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Feb 29, 2008
When the TRBPRE register is written continuously, allow three or more cycles of the count source for each
write interval.
When the TRBPR register is written continuously, allow three or more cycles of the prescaler underflow
for each write interval.
Workaround example (a):
As shown in Figure 21.2, write to registers TRBSC and TRBPR in the timer RB interrupt routine. These
write operations must be completed by the beginning of period A.
following points:
the TRBO output cycle using a timer RB interrupt, etc. This operation should be preformed only once in
the same output cycle. Also, make sure that writing to the TRBPR register does not occur during period
A shown in Figures 21.2 and 21.3.
The following shows the detailed workaround examples.
Programmable waveform generation mode
Workaround Example (a) When Timer RB interrupt is Used
TRBO pin output
(a) Period between interrupt request generation and the completion of execution of an instruction. The length of time
(b) 20 cycles. 21 cycles for address match and single-step interrupts.
underflow signal
varies depending on the instruction being executed.
The DIVX instruction requires the longest time, 30 cycles (assuming no wait states and that a register is set as
the divisor).
TRBIC register
Count source/
Interrupt request
is generated
prescaler
IR bit in
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(a)
sequence
Interrupt
(b)
Primary period
Interrupt request is
acknowledged
interrupt routine
Instruction in
Set the secondary and then
the primary register immediately
Ensure sufficient time
Secondary period
Period A
21. Usage Notes