DF2437FV Renesas Electronics America, DF2437FV Datasheet - Page 464

• 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: -

14.4
14.4.1
Figure 14.2 shows an example of duty measurement for the external event signal.
1. Select the external event signal whose duty needs to be measured by the IS2 to IS0 bits in
2. Select the count clock source for TWCNT by the CK2 to CK0 bits in TWCR1.
3. Write 1 to the START bit in TWCR2. At this time, TWCNT is cleared to H'00.
4. When a rising edge of the external event signal is detected, TWCNT starts counting. Then, if a
When TWICR and TWCNT values are read and then compared, duty measurement for the
external event signal is accomplished.
Rev.2.00 May. 28, 2009 Page 424 of 732
REJ09B0059-0200
falling edge of the external event signal is detected, the TWCNT value is transferred to
TWICR. If the second rising edge of the external event signal is detected, TWCNT stops
counting. At this time, the ENDF flag in TWCR2 is set to 1.
TWCR1.
Operation
Duty Measurement for External Event Signal
External event signal
Figure 14.2 Example of Duty Measurement for External Event Signal
Duty measurement
START signal
TWCNT
end flag
TWICR
H'00
M
N
TWCNT
clear
X
N
Count stop
t