HD64F3684FP Renesas Electronics America, HD64F3684FP Datasheet - Page 288

• Manufacturer Part Number: HD64F3684FP
• Description: IC H8 MCU FLASH 32K 64LQFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300H Tinyr

Specifications of HD64F3684FP

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: I²C, SCI
• Peripherals: PWM, WDT
• Number Of I /o: 45
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 4K 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: 64-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

Section 14 Watchdog Timer
14.3
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 14.2 shows an example of watchdog timer operation.
Rev.5.00 Nov. 02, 2005 Page 254 of 500
REJ09B0027-0500
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 14.2 Watchdog Timer Operation Example
6
H'F1 written
to TCWD
30
10
–3
Start
= 14.6
H'F1 written to TCWD
= 4 MHz
256
Reset generated
osc
TCWD overflow
clock cycles
osc
clock cycles. TCWD