MC68340PV16VE Freescale Semiconductor, MC68340PV16VE Datasheet - Page 122

• Manufacturer Part Number: MC68340PV16VE
• Description: IC MCU 32BIT 16MHZ 144-LQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68340PV16VE

• Processor Type: M683xx 32-Bit
• Speed: 16MHz
• Voltage: 3.3V
• Mounting Type: Surface Mount
• Package / Case: 144-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

SWT1, SWT0—Software Watchdog Timing
The software watchdog timeout period, listed in Table 4-7, gives the formula to derive the
software watchdog timeout for any clock frequency. The timeout periods are listed for a
32.768-kHz crystal used with the VCO and for a 16.777-MHz external oscillator.
DBFE—Double Bus Fault Monitor Enable
BME—Bus Monitor External Enable
BMT1, BMT0—Bus Monitor Timing
MOTOROLA
These bits, along with the SWP bit in the PITR, control the divide ratio used to establish
the timeout period for the software watchdog. The software watchdog timeout period is
given by the following formula:
NOTE: When the SWP and SWT bits are modified to select a software timeout other than the default, the
For more information, see 4.2.2.3 Double Bus Fault Monitor and Section 5 CPU32.
For more information see 4.2.2.2 Internal Bus Monitor.
These bits select the timeout period for the bus monitor (see Table 4-8). Upon reset, the
bus monitor is set to 64 system clocks.
SWP
1 = Enable double bus fault monitor function.
0 = Disable double bus fault monitor function.
1 = Enable bus monitor function for an internal-to-external bus cycle.
0 = Disable bus monitor function for an internal-to-external bus cycle.
0
0
0
0
1
1
1
1
software service sequence ($55 followed by $AA written to the software service register) must be
performed before the new timeout period takes effect. Refer to 4.2.2.5 Software Watchdog for
more information.
SWT1
0
0
1
1
0
0
1
1
SWT0
Table 4-7. Deriving Software Watchdog Timeout
0
1
0
1
0
1
0
1
Freescale Semiconductor, Inc.
For More Information On This Product,
2
2
2
2
2
2
2
2
Software Timeout Period
11
13
15
18
20
22
24
9
/EXTAL Input Frequency
/EXTAL Input Frequency
/EXTAL Input Frequency
/EXTAL Input Frequency
/EXTAL Input Frequency
/EXTAL Input Frequency
/EXTAL Input Frequency
/EXTAL Input Frequency
MC68340 USER’S MANUAL
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EXTAL frequency
divide count
Crystal Period
32.768-kHz
15.6 ms
62.5 ms
250 ms
128 s
512 s
32 s
1 s
8 s
16.777-MHz External
Clock Period
1.95 ms
15.6 ms
62.5 ms
250 ms
122 s
488 s
30 s
1 s
4- 25