R5F21257SNFP#U0 Renesas Electronics America, R5F21257SNFP#U0 Datasheet - Page 334

• Manufacturer Part Number: R5F21257SNFP#U0
• Description: IC R8C/25 MCU FLASH 52LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/2x/25r

Specifications of R5F21257SNFP#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: 48KB (48K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.5K 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
16.2.1
16.2.1.1
The transfer clock can be selected from among seven internal clocks (f1/256, f1/128, f1/64, f1/32, f1/16, f1/8,
and f1/4) and an external clock.
When using clock synchronous serial I/O with chip select, set the SCKS bit in the SSMR2 register to 1 and
select the SSCK pin as the serial clock pin.
When the MSS bit in the SSCRH register is set to 1 (operates as master device), an internal clock can be
selected and the SSCK pin functions as output. When transfer is started, the SSCK pin outputs clocks of the
transfer rate selected by bits CKS0 to CKS2 in the SSCRH register.
When the MSS bit in the SSCRH register is set to 0 (operates as slave device), an external clock can be selected
and the SSCK pin functions as input.
The association between the transfer clock polarity, phase and data changes according to the combination of the
SSUMS bit in the SSMR2 register and bits CPHS and CPOS in the SSMR register.
Figure 16.10 shows the Association between Transfer Clock Polarity, Phase, and Transfer Data.
Also, the MSB-first transfer or LSB-first transfer can be selected by setting the MLS bit in the SSMR register.
When the MLS bit is set to 1, transfer is started from the LSB and proceeds to the MSB. When the MLS bit is
set to 0, transfer is started from the MSB and proceeds to the LSB.
Feb 29, 2008
Transfer Clock
Association between Transfer Clock Polarity, Phase, and Data
Page 315 of 485
16. Clock Synchronous Serial Interface