HD64F3048VTF8 Renesas Electronics America, HD64F3048VTF8 Datasheet - Page 471

• Manufacturer Part Number: HD64F3048VTF8
• Description: IC H8 MCU FLASH 128K 100-QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300Hr

Specifications of HD64F3048VTF8

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 8MHz
• Connectivity: SCI, SmartCard
• Peripherals: DMA, PWM, WDT
• Number Of I /o: 70
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 100-TQFP, 100-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Other names: HD64F3048VX8

12.3
Operations when the WDT is used as a watchdog timer and as an interval timer are described
below.
12.3.1
Figure 12.4 illustrates watchdog timer operation. To use the WDT as a watchdog timer, set the
WT/IT and TME bits to 1 in TCSR. Software must prevent TCNT overflow by rewriting the
TCNT value (normally by writing H'00) before overflow occurs. If TCNT fails to be rewritten and
overflows due to a system crash etc., the chip is internally reset for a duration of 518 states.
The watchdog reset signal can be externally output from the RESO pin to reset external system
devices. The reset signal is output externally for 132 states. External output can be enabled or
disabled by the RSTOE bit in RSTCSR.
A watchdog reset has the same vector as a reset generated by input at the RES pin. Software can
distinguish a RES reset from a watchdog reset by checking the WRST bit in RSTCSR.
If a RES reset and a watchdog reset occur simultaneously, the RES reset takes priority.
H'FF
TCNT count
value
H'00
Internal
reset signal
RESO
Watchdog Timer Operation
Operation
Start
Figure 12.4 Watchdog Timer Operation
H'00 written
in TCNT
OVF = 1
WDT overflow
Rev. 7.00 Sep 21, 2005 page 445 of 878
132 states
Reset
518 states
TME set to 1
Section 12 Watchdog Timer
H'00 written
in TCNT
REJ09B0259-0700