HD64F36077GHV Renesas Electronics America, HD64F36077GHV Datasheet - Page 301

• Manufacturer Part Number: HD64F36077GHV
• Description: 16BIT MCU FLASH 56K, SMD, LQFP64
• Manufacturer: Renesas Electronics America

Specifications of HD64F36077GHV

• No. Of I/o's: 47
• Ram Memory Size: 4KB
• Cpu Speed: 20MHz
• No. Of Timers: 4
• Digital Ic Case Style: LQFP
• Supply Voltage Range: 4.5V
• Core Size: 16bit
• Program Memory Size: 56KB
• Oscillator Type: External Only
• Controller Family/series: H8/300H
• Peripherals: ADC
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14.3
The watchdog timer is provided with an 8-bit counter. After the reset state is released, TCWD
starts counting up. When the TCWD count value overflows H'FF, an internal reset signal is
generated. The internal reset signal is output for a period of 256 φ
writable counter, it starts counting from the value set in TCWD. An overflow period in the range
of 1 to 256 input clock cycles can therefore be set, according to the TCWD set value. When the
watchdog timer is not used, stop TCWD counting by writing 0 to B2WI and WDON
simultaneously while the TCSRWE bit in TCSRWD is set to 1. (To stop the watchdog timer, two
write accesses to TCSRWD are required.)
Figure 14.2 shows an example of watchdog timer operation.
Example:
Operation
Internal reset
signal
count value
TCWD
With 30-ms overflow period when φ = 4 MHz
Therefore, 256 – 15 = 241 (H'F1) is set in TCW.
H'FF
H'00
4 × 10
8192
H'F1
Figure 14.2 Watchdog Timer Operation Example
6
× 30 × 10
H'F1 written
to TCWD
–3
= 14.6
H'F1 written to TCWD
Rev. 1.00 Sep. 16, 2005 Page 271 of 490
256 φ
OSC
clock cycles. As TCWD is a
Reset generated
OSC
TCWD overflow
clock cycles
Section 14 Watchdog Timer
REJ09B0216-0100