DF2437FV Renesas Electronics America, DF2437FV Datasheet - Page 470

• Manufacturer Part Number: DF2437FV
• Description: IC H8S/2437 MCU FLASH 128QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8S/2400r

Specifications of DF2437FV

• Core Processor: H8S/2600
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: I²C, SCI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 85
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 128-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

14.7.2
If 1 is written to the START bit in TWCR2 while the FRC bit in TWCR1 is 1 as shown in figure
14.11, duty measurement is ignored and the START bit is cleared to 0.
14.7.3
The changeover may cause TWCNT to be incremented depending on the timing at which the
internal clock is switched (bits CKS2 to CKS0 are rewritten). Table 14.3 shows the relationship
between the timing and TCNT operation.
The TWCNT clock is generated on detection of the falling edge of the internal clock. If the clock
is changed when the old source is high and the new source is low, as in case no. 3 in table 14.3, the
changeover is regarded as a falling edge that generates the TWCNT clock, and TWCNT is
incremented.
Switching between an internal clock and external clock may also cause TWCNT to be
incremented. To prevent incorrect operation, ensure that TWCNT should be stopped before an
internal clock is changed.
Rev.2.00 May. 28, 2009 Page 430 of 732
REJ09B0059-0200
clear signal
write signal
START bit
START bit
TWCR2
FRC bit
Figure 14.11 Write to START Bit during Free-Running Counter Operation
Write to START Bit during Free-Running Counter Operation
Switching of Internal Clock and TWCNT Operation