PWM Control Bits
Bit 0x0203 Read/Write Initial Value
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
QUIET |
| SYNC_EN | RECIR |
| TODLY[2:0] |
| ENABLE |
R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W |
0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 |
Figure 2.6.16: PWM Control Bits
PWMCT
Bit 7 – QUIET
This bit changes PWM operation. When quiet is set, the bridge logic does not enter the reverse measure period, therefore there are fewer transitions. The bridge is disabled during zero cross. This mode is used at rest or when moving very slowly. When quiet is cleared, normal bridge operation is selected.
Bit 6 – Not used
Bit 5 – SYNC_EN
This bit controls the synchronization of the bridge PWM with the zero cross. When the sync_en bit is set, the bridge PWM will be synchronized with the positive front slope of the sin phase at each zero cross.
Bit 4 – RECIR
This bit controls where the motor current will recirculate within the bridge during the recirculate period. When recirc is set, the motor current will recirculate in the high portion of the bridge. When recir is cleared, the motor current will recirculate in the low portion of the bridge.
Bits 3..1 – TODLY - Turn on Delay
This value sets the bridge control turn on delay to prevent shoot through if a discrete FET bridge is in use. The range is 0 to 350 nS with 50 nS resolution. Each LSB is 50 nS. The default setting for a bridge driver is 50 nS (0x1).
Bit 0 – ENABLE
Bridge Enable, this bit is set at the factory and is inaccessible to the user.
Example PWM Settings By Motor Specifications
The following settings are based upon IMS settings per motor specifications and should serve as a baseline to work from with regard to the manufacturer specifications of the motor being utilized. Note that these are example settings ONLY!
Example PW Settings
Frame | Stack | Phase | Phase | Phase | MASK | Duty | Frequency | Checksum | |
Current | Resistance | Inductance | Cycle | ||||||
Size | Size | <mask> | <sfreq> | <chksum> | |||||
(ARMS) | (Ω) | (mH) | <period> | ||||||
|
|
|
|
| |||||
14 | Single | 0.75 | 4.30 | 4 | 102 | 90 | 170 | 106 | |
|
|
|
|
|
|
|
|
| |
| Single | 1.5 | 1.30 | 2.1 | 136 | 90 | 170 | 140 | |
17 | Double | 1.5 | 2.10 | 5.0 | 136 | 90 | 170 | 140 | |
| Triple | 1.5 | 2.00 | 3.85 | 136 | 90 | 170 | 140 | |
| Single |
|
|
|
|
|
|
| |
| 2.4 | 0.95 | 2.4 | 136 | 90 | 170 | 140 | ||
23 | Double | 2.4 | 1.20 | 4.0 | 136 | 90 | 170 | 140 | |
| Triple | 2.4 | 1.50 | 5.4 | 136 | 90 | 170 | 140 |
MForce Default
—
—
—
204
95
170
—
Table 2.6.9: Example PWM Settings
40 | Microstepping MForce PowerDrive Manual Revision R032008 |
