Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
174 Pulse-Width Modulator for Motor Control (PWM MC) MOTOROLA
Pulse-Width Modulator for Motor Control
LDFQ1 and LDFQ0 — PWM Load Frequency Bits
These buffered read/write bits select the PWM CPU load frequency
according to Table 9-8.
NOTE: When reading these bits, the value read is the buffer value (not
necessarily the value the PWM generator is currently using).
The LDFQx bits take effect when the current load cycle is complete
regardless of the state of the load okay bit, LDOK.
NOTE: Reading the LPFQx bit reads the buffered values and not necessarily the
values currently in effect.
IPOL1 — Top/Bottom Correction Bit for PWM Pair 1 (PWMs 1 and 2)
This buffered read/write bit selects which PWM value register is us ed
if top/bottom correction is to be achieved without current sensing.
1 = Use PWM value register 2.
0 = Use PWM value register 1.
NOTE: When reading this bit, the value read is the buffer val ue (not necessa rily
the value the output control block is currently using).
Address: $0021
Bit 7654321Bit 0
Read: LDFQ1 LDFQ0 0IPOL1 IPOL2 IPOL3 PRSC1 PRSC0
Write:
Reset:00000000
= Unimplemented Bo ld = Buffered
Figure 9-39. PWM Control Register 2 (PCTL2)
Table 9-8. PWM Reload Frequency
Reload Frequency Bits
LDFQ1 and LDFQ0 PWM Reload Frequency
00 Every PWM cycle
01 Every 2 PWM cycles
10 Every 4 PWM cycles
11 Every 8 PWM cycles