50.5.7 Configuration Limitations
Some limitations exist for the DSP configuration when associating several DSPs to a single transmit or receive holding register.
When ASRC_CH_CONF.RHROPMODE>0, the DSPs sharing the same ASRC_RHRx must have the same output sampling frequency, configured by ASRC_RATIOx.OUTRATIO and ASRC_TRIG.
When ASRC_CH_CONF.THROPMODE>0, the DSPs sharing the same ASRC_THRx must have the same input sampling frequency, configured by ASRC_RATIOx.INRATIO and ASRC_TRIG.
When ASRC_CH_CONF.RHROPMODE>0 or ASRC_CH_CONF.THROPMODE>0, the mono or stereo configuration of DSPs are limited to the values described in the figures shown above.
The configuration of DMA transfer chunk size has some restrictions listed in the table below. The DMA receives fewer requests to transfer data when the chunk size is high. Therefore, it reduces the overhead processing for each transfer request and leads to improved performance at system level.
Major configuration errors are reported in ASRC_ESR. For details, see ASRC_ESR.
| ASRC_CH_CONF.THROPMODE / ASRC_CH_CONF.RHROPMODE | ||||||
|---|---|---|---|---|---|---|
| Value | 0 | 1,2,3(1) | 4 | |||
| DSP | Mono | Stereo | Mono | Stereo | Mono | Stereo |
| C H U N K x |
1 | 1 | 1 | 1 | 1 | 1 |
| 2 | 2 | 2 | 2 | 2 | 2 | |
| 4 | 4 | 4 | 4 | 4 | 4 | |
| Forbidden | 8 | 8 | 8 | 8 | 8 | |
| Forbidden | Forbidden | Forbidden | 16 | 16 | 16 | |
- Applies only to ASRC_RHRx/THRx sharing a DSP. The chunk limitation for ASRC_RHRx/THRx driving one DSP is the same as the limitation for THROPMODE/RHROPMODE=0.