39
Part 2: Interfacing and Configuring
Typical PWM Mask Settings (Currents Balanced)
Mask
(hex)
Mask
(dec)
REVTM FORTM
Mask
(hex)
Mask
(dec)
REVTM FORTM
0x00 0 600 ns 600 ns 0x88 135 1.6 µs 1.6 µs
0x11 17 700 ns 700 ns 0x99 153 1.8 µs 1.8 µs
0x22 34 800 ns 800 ns 0xAA 170 2.0 µs 2.0 µs
0x33 51 900 ns 900 ns 0xBB 187 2.2 µs 2.2 µs
0x44 68 1.0 µs 1.0 µs 0xCC 204 2.5 µs 2.5 µs
0x55 85 1.1 µs 1.1 µs 0xDD 221 2.8 µs 2.8 µs
0x66 102 1.2 µs 1.2 µs 0xEE 238 3.1 µs 3.1 µs
0x77 119 1.4 µs 1.4 µs 0xFF 255 3.4 µs 3.4 µs
Table 2.6.7: Typical PWM Mask Settings
Maximum PWM Duty Cycle (%) Parameter
This parameter sets the maximum duty cycle as a percentage of the bridge PWM oscillator period. The range
for this parameter is 0 to 95%. The default value for this parameter is 95%.
PWM Frequency Range Parameter
The PWM Frequency Parameter sets the initial and maximum frequencies for the PWM. As with the MASK
parameter, the PWM Frequency is a two part 8-bit hex number which is entered as a decimal value ranging
from 0 to 255.
The default for this 170 (0xAA) with an initial PWM Frequency of 20 kHz and a Maximum of 60 kHz.
Maximum PWM Frequency (kHz)
Hex Freq. Hex Freq Hex Freq Hex Freq
0x0 40 0x4 48 0x8 56 0xC 64
0x1 42 0x5 50 0x9 58 0xD 66
0x2 44 0x6 52 0xA 60 0xE 68
0x3 46 0x7 54 0xB 62 0xF 70
Initial PWM Frequency (kHz)
Hex Freq. Hex Freq Hex Freq Hex Freq
0x0 10 0x4 14 0x8 18 0xC 22
0x1 11 0x5 15 0x9 19 0xD 23
0x2 12 0x6 16 0xA 20 0xE 24
0x3 13 0x7 17 0xB 21 0xF 25
Table 2.6.8: Maximum and Initial PWM Frequency
PWM Max. Frequency PWM Initial Frequency
0 1 0 1 1 1 1 0
0x5 (50 kHz) 0xE (24 kHz)
0x5E
PWM SFREQ = 94
PWM Frequency Range 24 to 50 kHz
Convert to Decimal
Figure 2.6.15: PWM Frequency Range
