SPRUJF8 May 2026 TMS320F28P551SG
Primary (data) filters can be synchronized with respect to the PWM event (called SDSYNC event). The SDSYNC signal from the PWM module is used to reset the DOSR counter. This feature is by default disabled and can be enabled by setting SDDFPARMx.SDSYNCEN = 1. Each primary filter can be synchronized from any of the available PWMx SOCA/SOCB signals (see Table 21-5). The SDSYNCx.SDSYNCSEL bits allow the user to configure which PWM signal provides the SDSYNC pulse to the primary filter. Figure 21-10 shows how device PWM signals are connected to the SDFM modules.
| SYNCSEL[5:2] | SYNCSEL[1:0]=0 | SYNCSEL[1:0]=1 | SYNCSEL[1:0]=2 | SYNCSEL[1:0]=3 |
|---|---|---|---|---|
| 0 | PWM1.SOCA | PWM1.SOCB | Rsvd | Rsvd |
| 1 | PWM2.SOCA | PWM2.SOCB | Rsvd | Rsvd |
| 2 | PWM3.SOCA | PWM3.SOCB | Rsvd | Rsvd |
| 3 | PWM4.SOCA | PWM4.SOCB | Rsvd | Rsvd |
| 4 | PWM5.SOCA | PWM5.SOCB | Rsvd | Rsvd |
| 5 | PWM6.SOCA | PWM6.SOCB | Rsvd | Rsvd |
| 6 | PWM7.SOCA | PWM7.SOCB | Rsvd | Rsvd |
| 7 | PWM8.SOCA | PWM8.SOCB | Rsvd | Rsvd |
| 8 | PWM9.SOCA | PWM9.SOCB | Rsvd | Rsvd |
| 9 | PWM10.SOCA | PWM10.SOCB | Rsvd | Rsvd |
| 10 | PWM11.SOCA | PWM11.SOCB | Rsvd | Rsvd |
| 11 | PWM12.SOCA | PWM12.SOCB | Rsvd | Rsvd |
| 14:12:00 | Rsvd | Rsvd | Rsvd | Rsvd |
| 15 | Rsvd | Rsvd | Rsvd | SDFM1.SDSYNC1 - PWM11.CMPC SDFM1.SDSYNC2 - PWM11.CMPC SDFM1.SDSYNC3 - PWM11.CMPD SDFM1.SDSYNC4 - PWM11.CMPD SDFM2.SDSYNC1 - PWM12.CMPC SDFM2.SDSYNC2 - PWM12.CMPC SDFM2.SDSYNC3 - PWM12.CMPD SDFM2.SDSYNC4 - PWM12.CMPD |
Figure 21-10 SDSYNC EventBecause of the inherent architecture of the Sinc filter (Sinc1, Sinc2, Sinc3, SincFast), the first few samples, depending upon filter type, are incorrect. Table 21-6 shows the number of incorrect samples on the following conditions:
| Filter Type | Number of Incorrect Samples After the Filter is Enabled and Configured |
|---|---|
| Sinc1 | No incorrect sample. |
| Sinc2 | The first sample of the Sinc2 filter is incorrect. |
| SincFast | The first two samples of the SincFast filter are incorrect. |
| Sinc3 | The first two samples of the Sinc3 filter are incorrect. |