SPRUJ55D September 2023 – July 2025 AM263P2 , AM263P2-Q1 , AM263P4 , AM263P4-Q1
The PRU uses the R30 and R31 registers to interface with the Sigma Delta interface. Table 7-48 and Table 7-49 shows the R31 and R30 interface for the Sigma Delta mode. Note that only the parameters and data for one channel can be viewed at a time. The channel to be viewed is determined by the r30[29-26] (channel_select).
| Bits | Field Name | Description |
|---|---|---|
| 31-30 | Reserved | |
| 29 | shadow_update_flag_ovf | Shadow update flag overflow, set when over sample count equals over sample size and shadow_update_flag is still set. Set bit R31[24] to clear the flag. |
| 28 | shadow_update_flag | Shadow update flag, set when over sample count equals over sample size and shadow_update_flag is still set. Set bit R31[24] to clear the flag. |
| 27-0 | data_out[27-0]/ shadow_update_flag_clr (R31[24]) / re_init (R31[23]) | data_out[27] (read): most-significant bit of sample data shadow_update_flag_clr (write): re_init (write): Set to reset all counters, flags, and shadow copy. Updates over_sample_size based on the current PRU_ICSS_PRU0_SD_SAMPLE_SIZEi[7-0] register (where n = 0 or 1 and i = 0 to 8) on the selected channel. shadow_update_flag_clr (write): Set to clear shadow_update_flag and shadow_update_flag_ovf (if set). |
| Bits | Field Name | Description |
|---|---|---|
| 31-30 | Reserved | |
| 29-26 | channel_select[3-0] | Channel select 0h: Channel 0 ... 8h: Channel 8 9h: Reserved ... Fh: Reserved |
| 25 | channel_en | Global Channel enable (effects all 9 channels). 0h: All channels disabled. Counters/flags are cleared. 1h: All channels enabled. |
| 24-23 | Reserved | |
| 22 | snoop | Enable snoop (i.e. fetch data) on the selected channel. 0h: acc1/acc2/acc3 shadow copy 1h: current acc1/acc2/acc3 |
| 21 | sample_counter_select | Read sample counter. 0h: Not selected 1h: Sample count selected |
| 20-0 | Reserved |
The PRU-ICSS CFG register space has additional registers for controlling the SD demodulator module: