DF71251AD50FPV Renesas Electronics America, DF71251AD50FPV Datasheet - Page 87

• Manufacturer Part Number: DF71251AD50FPV
• Description: MCU RISC FLASH 32K 8K 64LQFP
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH Tinyr

Specifications of DF71251AD50FPV

• Core Processor: SH-2
• Core Size: 32-Bit
• Speed: 50MHz
• Connectivity: SCI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 37
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

4.5
Selecting division ratios for the frequency divider can change the frequencies of the internal clock
(Iφ), bus clock (Bφ), peripheral clock (Pφ), and MTU2 clock (MPφ). This is controlled by software
through the frequency control register (FRQCR). The following describes how to specify the
frequencies.
1. In the initial state, IFC2 to IFC0 = H'011 (×1/4), BFC2 to BFC0 = H'011 (×1/4), PFC2 to
2. Stop all modules except the CPU, on-chip ROM, and on-chip RAM.
3. Set the desired values in bits IFC2 to IFC0, BFC2 to BFC0, PFC2 to PFC0, and MPFC2 to
4. After an instruction to rewrite FRQCR has been issued, the actual clock frequencies will
PFC0 = H'011 (×1/4), and MPFC2 to MPFC0 = H'011 (×1/4).
MPFC0 bits. Since the frequency multiplication ratio in the PLL circuit is fixed at ×8, the
frequencies are determined only be selecting division ratios. When specifying the frequencies,
satisfy the following condition: internal clock (Iφ) ≥ bus clock (Bφ) = peripheral clock (Pφ).
When using the MTU2 clock, specify the frequencies to satisfy the following condition:
internal clock (Iφ) ≥ MTU2 clock (MPφ) ≥ peripheral clock (Pφ).
change after (1 to 24n) cyc + 11Bφ + 7Pφ.
n: Division ratio specified by the BFC bit in FRQCR (1/2, 1/4, or 1/8)
cyc: Clock obtained by dividing EXTAL by 8 with the PLL.
Note: (1 to 24n) depends on the internal state.
Changing Frequency
Rev. 5.00 Mar. 06, 2009 Page 67 of 770
REJ09B0243-0500