R5F2121AJFP#U0 Renesas Electronics America, R5F2121AJFP#U0 Datasheet - Page 160

• Manufacturer Part Number: R5F2121AJFP#U0
• Description: MCU FLASH 96K 5K CMOS 48-LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/2x/21r

Specifications of R5F2121AJFP#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: 96KB (96K x 8)
• Program Memory Type: FLASH
• Ram Size: 5K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

R8C/20 Group, R8C/21 Group
Rev.2.00 Aug 27, 2008
REJ09B0250-0200
14.2.1.1
Timer RB has a prescaler and a timer (which counts the prescaler underflows). The prescaler and timer each
consist of a reload register and a counter. In timer mode, the TWRC bit in the TRBMR register can be used to
select whether writing to the prescaler or timer during count operation is performed to both the reload register
and counter or only to the reload register.
However, values are transferred from the reload register to the counter of the prescaler in synchronization with
the count source. In addition, values are transferred from the reload register to the counter of the timer in
synchronization with prescaler underflows. Therefore, even if the TWRC bit is set for writing to both the reload
register and counter, the counter value is not updated immediately after the WRITE instruction is executed. In
addition, if the TWRC bit is set for writing to the reload register only, the synchronization of the writing will be
shifted if the prescaler value changes.
Figure 14.18 shows an Operating Example of Timer RB when Counter Value is Rewritten during Count
Operation.
Timer Write Control during Count Operation
Page 142 of 458
14. Timers