20-668-0003 Rabbit Semiconductor, 20-668-0003 Datasheet - Page 87

• Manufacturer Part Number: 20-668-0003
• Description: IC CPU RABBIT2000 30MHZ 100PQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0003

• Processor Type: Rabbit 2000 8-Bit
• Speed: 30MHz
• Voltage: 2.7V, 3V, 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 100-MQFP, 100-PQFP
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 30 MHz
• Operating Supply Voltage: 0 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 40
• Number Of Timers: 8 & 10 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 20-668-0003; 316-1062

The code to do this may also hit the watchdog with a 0.25-second period to speed up the
reset. Such watchdog code must be written so that it is highly unlikely that a crash will
incorporate the code and continue to hit the watchdog in an endless loop. The following
suggestions will help.
1. Place a jump to self before the entry point of the watchdog hitting routines. This pre-
2. Before calling the routine, set a data byte to a special value and then check it in the rou-
3. Maintain data corruption flags and/or checksums. If these go wrong, go into an endless
Chapter 7 Miscellaneous I/O Functions
7:0
vents entry other than by a direct call or jump to the routine.
tine to make sure the call came from the right caller. If not, go into an endless loop with
interrupts disabled.
loop with interrupts off.
Bit(s)
Table 7-9. Watchdog Timer Test Register (WDTTR adr = 0x09)
0x51
0x52
0x53
0x54
other
Value
Clock the least significant byte of the WDT timer from the peripheral
clock. (Intended for chip test and code 0x54 below only.)
Clock the most significant byte of the WDT timer from the peripheral
clock. (Intended for chip test and code 0x54 below only.)
Clock both bytes of the WDT timer, in parallel, from the peripheral clock.
(Intended for chip test and code 0x54 below only.)
Disable the WDT timer. This value, by itself, does not disable the WDT
timer. Only a sequence of two writes, where the first write is 0x51, 0x52 or
0x53, followed by a write of 0x54, actually disables the WDT timer. The
WDT timer will be re-enabled by any other write to this register.
Normal clocking (32 kHz oscillator) for the WDT timer. This is the
condition after reset.
Description
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