MC68HC908LB8CPE Freescale Semiconductor, MC68HC908LB8CPE Datasheet - Page 155

• Manufacturer Part Number: MC68HC908LB8CPE
• Description: IC MCU 8K FLASH 8MHZ 20DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908LB8CPE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LVR, POR, PWM
• Number Of I /o: 18
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

The 16-bit signed value stored in this register determines the duty cycle of the PWM. The duty cycle is
defined as:
(PWM value/modulus) x 100
Writing a number less than or equal to 0 causes the PWM to be off for the entire PWM period. Writing a
number greater than or equal to the 12-bit modulus causes the PWM to be on for the entire PWM period.
To avoid erroneous PWM pulses, this value is buffered and will not be used by the PWM generator until
the LDOK bit has been set and the next PWM load cycle begins.
15.8.4 PWM Control Register 1
PWM control register 1 (PCTL1) controls PWM enabling/disabling, the location of the PWM Fault bit, the
loading of new modulus, prescaler, PWM values, and the PWM correction method.
FPOS — Fault Pin Position Bit
PWMINT — PWM Interrupt Enable Bit
Freescale Semiconductor
This read/write bit allows the user to select the location of the Fault pin.
This read/write bit allows the user to enable and disable PWM CPU interrupts. If set, a CPU interrupt
will be pending when the PWMF flag is set.
1 = Fault pin functionality is placed on PTB2
0 = Fault pin functionality is placed on PTB7
1 = Enable PWM CPU interrupts
0 = Disable PWM CPU interrupts
Address:
When reading these registers, the value read is the buffer (not necessarily
the value the PWM generator is currently using).
Placing the Fault pin on PTB7 will not affect the ADC or the op
amp/comparator connections. This is to allow the output of the op
amp/comparator to be used as the input to the Fault pin and for this same
signal to be simultaneously measured by the ADC.
Reset:
Reset:
Read:
Read:
Write:
Write:
$0040
Bit 7
Bit 7
Bold
Bit 7
Figure 15-19. PWMx Value Registers Low (PVALxL)
0
0
0
Figure 15-20. PWM Control Register 1 (PCTL1)
= Buffered
= Unimplemented
FPOS
Bit 6
6
0
6
0
MC68HC908LB8 Data Sheet, Rev. 1
PWMINT
Bit 5
5
0
5
0
NOTE
NOTE
PWMF
Bit 4
4
0
4
0
Bit 3
3
0
3
0
0
Bit 2
2
0
2
0
0
LDOK
Bit 1
1
0
1
0
PWMEN
Control Logic Block
Bit 0
Bit 0
Bit 0
0
0
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