Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
154 Pulse-Width Modulator for Motor Control (PWM MC) MOTOROLA
Pulse-Width Modulator for Motor Control
Figure 9-17. Ideal Complementary Operation (Dead-Time = 0)
NOTE: This text assumes the user will provide current sense circuitry which
causes the voltage at the corresponding input pin to be low for positive
current and high for negative current. See Figure 9-18 for current
convention. In addition, it assumes the top PWMs are PWMs 1, 3, and 5
while the bottom PWMs are PWMs 2, 4, and 6.
UP/DOWN COUNTER
MODULUS = 4
PWM VALUE = 1
PWM1
PWM2
PWM VALUE = 2
PWM3
PWM4
PWM VALUE = 3
PWM5
PWM6
Table 9-4. Current Sense Pins
Current
Sense Pin
or Bit
Voltage
on Current
Sense Pin
or IPOLx Bit
PWM Value
Register Used PWMs
Affected
IS1 or IPOL1 Logic 0 PWM value register 1 PWMs 1 and 2
IS1 or IPOL1 Logic 1 PWM value register 2 PWMs 1 and 2
IS2 or IPOL2 Logic 0 PWM value register 3 PWMs 3 and 4
IS2 or IPOL2 Logic 1 PWM value register 4 PWMs 3 and 4
IS3 or IPOL3 Logic 0 PWM value register 5 PWMs 5 and 6
IS3 or IPOL3 Logic 1 PWM value register 6 PWMs 5 and 6