HD6417751RF240V Renesas Electronics America, HD6417751RF240V Datasheet - Page 389

• Manufacturer Part Number: HD6417751RF240V
• Description: MPU 1.5/3.3V 0K PB-FREE 256-QFP
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH7750r

Specifications of HD6417751RF240V

• Core Processor: SH-4
• Core Size: 32-Bit
• Speed: 240MHz
• Connectivity: EBI/EMI, FIFO, SCI, SmartCard
• Peripherals: DMA, POR, WDT
• Number Of I /o: 39
• Program Memory Type: ROMless
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.4 V ~ 1.6 V
• Oscillator Type: External
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 256-QFP Exposed Pad, 256-eQFP, 256-HQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

10.11
10.11.1 Invalid Manual Reset Triggered by Watchdog Timer (SH7751 Only)
Under certain conditions the on-chip watchdog timer (WDT) may trigger an invalid manual reset.
Conditions Under which Problem Occurs: The on-chip WDT triggers an invalid manual reset
when all of the following four conditions are satisfied.
1. After the WDT overflows, regardless of the values of the WT/IT and RSTS bits in WTCSR.
2. Before the counter (WTCNT) is incremented by the clock specified by the WTCSR.CKS bit.
3. The value of at least one of the TME, WT/IT, and RSTS bits in WTCSR is 0.
4. A value of 1 is written to the TME, WT/IT, and RSTS bits in WTCSR.
Workaround: A workaround for this problem is to use software to increment WTCNT before
writing 1 to the TME, WT/IT, and RSTS bits in WTCSR. Specific lines of code for this purpose
are listed below.
Example: Add the following lines of code before the instructions for writing 1 to the TME,
WT/IT, and RSTS bits in WTCSR.
L.OOP_WDT:
Usage Notes
MOV.L #WTCNT,R7
MOV.W #H'5A00,R8
MOV.W R8,@R7
MOV.L #WTCSR,R9
MOV.W #H'A580,R10
MOV.W R10,@R9
MOV.B @R7,R0
CMP/EQ #H'00, R0
BT
L.OOP_WDT
Rev.4.00 Oct. 10, 2008 Page 289 of 1122
10. Clock Oscillation Circuits
REJ09B0370-0400