HD6417144F50V Renesas Electronics America, HD6417144F50V Datasheet - Page 431

• Manufacturer Part Number: HD6417144F50V
• Description: IC SUPERH MCU ROMLESS 112QFP
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH7144r

Specifications of HD6417144F50V

• Core Processor: SH-2
• Core Size: 32-Bit
• Speed: 50MHz
• Connectivity: EBI/EMI, I²C, SCI
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 74
• Program Memory Type: ROMless
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 112-QFP
• For Use With: HS0005KCU11H - EMULATOR E10A-USB H8S(X),SH2(A)EDK7145 - DEV EVALUATION KIT SH7145
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

12.4
12.4.1
To use the WDT as a watchdog timer, set the WT/IT and TME bits of TCSR to 1. Software must
prevent TCNT overflow by rewriting the TCNT value (normally by writing H'00) before overflow
occurs. No TCNT overflows will occur while the system is operating normally, but if TCNT fails
to be rewritten and overflows occur due to a system crash or the like, a WDTOVF signal is output
externally. The WDTOVF signal can be used to reset the system. The WDTOVF signal is output
for 128φ clock cycles.
If the RSTE bit in RSTCSR is set to 1, a signal to reset the chip will be generated internally
simultaneous to the WDTOVF signal when TCNT overflows. Either a power-on reset or a manual
reset can be selected by the RSTS bit in RSTCSR. The internal reset signal is output for 512 φ
clock cycles.
When a WDT overflow reset is generated simultaneously with a reset input at the RES pin, the
RES reset takes priority, and the WOVF bit in RSTCSR is cleared to 0.
The following are not initialized by a WDT reset signal:
• Port output enable (POE) registers of MTU
• Pin function controller (PFC) registers
• I/O port registers
• Reset control/status register (RSTCSR) of watchdog timer (WDT)
These registers are initialized only by an external power-on reset.
Besides, TCNT and TCSR of the WDT are not initialized by a manual reset from the MRES pin,
but are initialized by an internal manual reset generated by a WDT overflow.
Operation
Watchdog Timer Mode
Rev.4.00 Mar. 27, 2008 Page 385 of 882
12. Watchdog Timer
REJ09B0108-0400