R5F21191SP#U0 Renesas Electronics America, R5F21191SP#U0 Datasheet - Page 133

• 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: -

R8C/18 Group, R8C/19 Group
Rev.1.30
REJ09B0222-0130
14.1.6
•
•
•
•
•
•
•
•
Apr 14, 2006
Timer X stops counting after a reset. Set the values in the timer and prescaler before the count
starts.
Even if the prescaler and timer are read out in 16-bit units, these registers are read 1 byte at a
time by the MCU. Consequently, the timer value may be updated during the period when these
two registers are being read.
Do not rewrite bits TXMOD0 to TXMOD1, and bits TXMOD2 and TXS simultaneously.
In pulse period measurement mode, bits TXEDG and TXUND in the TXMR register can be set to
0 by writing 0 to these bits by a program. However, these bits remain unchanged if 1 is written.
When using the READ-MODIFY-WRITE instruction for the TXMR register, the TXEDG or TXUND
bit may be set to 0 although these bits are set to 1 while the instruction is being executed. In this
case, write 1 to the TXEDG or TXUND bit which is not supposed to be set to 0 with the MOV
instruction.
When changing to pulse period measurement mode from another mode, the contents of bits
TXEDG and TXUND are undefined. Write 0 to bits TXEDG and TXUND before the count starts.
The TXEDG bit may be set to 1 by the prescaler X underflow generated after the count starts.
When using the pulse period measurement mode, leave two or more periods of the prescaler X
immediately after the count starts, then set the TXEDG bit to 0.
The TXS bit in the TXMR register has a function to instruct timer X to start or stop counting and a
function to indicate that the count has started or stopped.
0 (count stops) can be read until the following count source is applied after 1 (count starts) is
written to the TXS bit while the count is being stopped. If the following count source is applied, 1
can be read from the TXS bit. After writing 1 to the TXS bit, do not access registers associated
with timer X (registers TXMR, PREX, TX, TCSS, and TXIC) except for the TXS bit, until 1 can be
read from the TXS bit. The count starts at the following count source after the TXS bit is set to 1.
Also, after writing 0 (count stops) to the TXS bit during the count, timer X stops counting at the
following count source.
1 (count starts) can be read by reading the TXS bit until the count stops after writing 0 to the TXS
bit. After writing 0 to the TXS bit, do not access registers associated with timer X except for the
TXS bit, until 0 can be read from the TXS bit.
Notes on Timer X
Page 116 of 233
14. Timers