HD64F3694FY Renesas Electronics America, HD64F3694FY Datasheet - Page 217

• Manufacturer Part Number: HD64F3694FY
• Description: IC H8 MCU FLASH 32K 48-LQFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300H Tinyr

Specifications of HD64F3694FY

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: I²C, SCI
• Peripherals: PWM, WDT
• Number Of I /o: 29
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

13.3
The watchdog timer is provided with an 8-bit counter. If 1 is written to WDON while writing 0 to
B2WI when the TCSRWE bit in TCSRWD is set to 1, TCWD begins counting up. (To operate
the watchdog timer, two write accesses to TCSRWD are required.) When a clock pulse is input
after the TCWD count value has reached H'FF, the watchdog timer overflows and an internal reset
signal is generated. The internal reset signal is output for a period of 256
is a writable counter, and when a value is set in TCWD, the count-up starts from that value. An
overflow period in the range of 1 to 256 input clock cycles can therefore be set, according to the
TCWD set value.
Figure 13.2 shows an example of watchdog timer operation.
Example:
Operation
Internal reset
signal
count value
TCWD
With 30ms overflow period when
Therefore, 256 – 15 = 241 (H'F1) is set in TCW.
H'FF
H'00
4
8192
10
H'F1
Figure 13.2 Watchdog Timer Operation Example
6
H'F1 written
to TCWD
30
10
–3
Start
= 14.6
H'F1 written to TCWD
= 4 MHz
Rev.5.00 Nov. 02, 2005 Page 187 of 418
256
Reset generated
osc
TCWD overflow
clock cycles
Section 13 Watchdog Timer
osc
clock cycles. TCWD
REJ09B0028-0500