MC68HC912B32VFU8 Freescale Semiconductor, MC68HC912B32VFU8 Datasheet - Page 139

• Manufacturer Part Number: MC68HC912B32VFU8
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC912B32VFU8

• Cpu Family: HC12
• Device Core Size: 16b
• Frequency (max): 8MHz
• Interface Type: SCI/SPI
• Program Memory Type: EPROM
• Program Memory Size: 32KB
• Total Internal Ram Size: 1KB
• # I/os (max): 63
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• On-chip Adc: 8-chx10-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 105C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 80
• Package Type: PQFP
• Lead Free Status / Rohs Status: Not Compliant

11.4.1 PWM Period Calculation
These parameters were used to calculate the high-time values shown in
Table
11.4.2 Equipment
For this exercise, use the M68HC912B32EVB emulation board.
Freescale Semiconductor
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11-3:
Period = $1000 (Hex) = 4096 (decimal)
E clock = 8 MHz
Prescaler = 4
Frequency = (8 MHz) / (#clocks_count*prescaler) = (8 MHz) (4096*4)
= 500 Hz
If period ($4096 Clocks) => frequency = 500 Hz
HEX Count
$0D9A
$0C00
$0020
$0040
$0080
$0100
$0200
$0040
$0080
$0996
$1000
High-Time Values
Table 11-3. PWM Period Calculations
M68HC12B Family Data Sheet, Rev. 9.1
Decimal Count
1024
2048
2454
3072
3482
4096
128
256
512
32
64
Using the Output Compare 7 Feature to Generate a PWM
Duty Cycle
100.00%
12.50%
25.00%
50.00%
60.00%
75.00%
85.00%
6.25%
1.5%
3.1%
0%
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