MC68HC908MR8CFA Freescale Semiconductor, MC68HC908MR8CFA Datasheet - Page 169

• Manufacturer Part Number: MC68HC908MR8CFA
• Description: IC MCU 8K FLASH 8MHZ PWM 32-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908MR8CFA

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 16
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

9.8 Initialization and the PWMEN Bit
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
CPU CLOCK
PWM PINS
PWMEN
NOTE:
HI-Z IF OUTCTL = 0
For proper operation, all registers should be initialized and the LDOK bit
should be set before enabling the PWM via the PWMEN bit. When the
PWMEN bit is first set, a reload will occur immediately, setting the PWMF
flag and generating an interrupt if PWMINT is set. In addition, in
complementary mode, PWM value registers 1, 3, and 5 will be used for
the first PWM cycle if current sensing is selected.
If the LDOK bit is not set when PWMEN is set after a RESET, the
prescaler and PWM values will be 0, but the modulus will be unknown.
If the LDOK bit is not set after the PWMEN bit has been cleared then set
(without a RESET), the modulus value that was last loaded will be used.
If the dead-time register (DEADTM) is changed after PWMEN or
OUTCTL is set, an improper dead-time insertion could occur. However,
the dead-time can never be shorter than the specified value.
Because of the equals-comparator architecture of this PWM, the
modulus = 0 case is considered illegal. Therefore, the modulus register
is not reset, and a modulus value of 0 will result in waveforms
inconsistent with the other modulus waveforms. See
Counter Modulo
When PWMEN is set, the PWM pins change from high impedance to
outputs. At this time, assuming no fault condition is present, the PWM
pins will drive according to the PWM values, polarity, and dead-time.
See the timing diagram in
Pulse-Width Modulator for Motor Control (PWMMC)
Figure 9-28. PWMEN and PWM Pins
Registers.
VALUE, POLARITY, AND DEAD-TIME
DRIVE ACCORDING TO PWM
Figure
Pulse-Width Modulator for Motor Control (PWMMC)
9-28.
Initialization and the PWMEN Bit
HI-Z IF OUTCTL = 0
9.12.2 PWM
Technical Data
169