DF3052BX25V Renesas Electronics America, DF3052BX25V Datasheet - Page 460

• Manufacturer Part Number: DF3052BX25V
• Description: MCU 5V 512K 100-TQFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300Hr

Specifications of DF3052BX25V

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 25MHz
• Connectivity: SCI, SmartCard
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 70
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 4.5 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: Lead free / RoHS Compliant
• Eeprom Size: -

Section 12 Watchdog Timer
Reading TCNT, TCSR, and RSTCSR: These registers are read like other registers. Byte access
instructions can be used. The read addresses are H'FFA8 for TCSR, H'FFA9 for TCNT, and
H'FFAB for RSTCSR, as listed in table 12.2.
Table 12.2 Read Addresses of TCNT, TCSR, and RSTCSR
Address *
H'FFA8
H'FFA9
H'FFAB
Note: * Lower 16 bits of the address.
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.
A reset generated by the WDT 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.
Rev. 3.00 Mar 21, 2006 page 430 of 814
REJ09B0302-0300
Operation
Watchdog Timer Operation
Register
TCSR
TCNT
RSTCSR