SPRUIM2H May 2020 – October 2023 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442
The Sigma Delta’s I/Os are multiplexed with the PRU GPI/GPO signals, as shown in Table 6-417.
Note: The PR<k>_PRU<n>_GP_MUX_SEL bitfield in the ICSSG_GPCFG0_REG register (where k = 0 or 1 and n = 0 or 1) must be set to 3h for configure the GPI/GPO signals for SD mode.
Signal Names at Device Level (1) | Sigma Delta (SD) Mode | Function |
---|---|---|
PRG<k>_PRU<n>_GPI0 | SD0_CLK | SD demodulator clock channel 0 |
PRG<k>_PRU<n>_GPI1 | SD0_D | SD demodulator data channel 0 |
PRG<k>_PRU<n>_GPI2 | SD1_CLK | SD demodulator clock channel 1 |
PRG<k>_PRU<n>_GPI3 | SD1_D | SD demodulator data channel 1 |
PRG<k>_PRU<n>_GPI4 | SD2_CLK | SD demodulator clock channel 2 |
PRG<k>_PRU<n>_GPI5 | SD2_D | SD demodulator data channel 2 |
PRG<k>_PRU<n>_GPI6 | SD3_CLK | SD demodulator clock channel 3 |
PRG<k>_PRU<n>_GPI7 | SD3_D | SD demodulator data channel 3 |
PRG<k>_PRU<n>_GPI8 | SD4_CLK | SD demodulator clock channel 4 |
PRG<k>_PRU<n>_GPI9 | SD4_D | SD demodulator data channel 4 |
PRG<k>_PRU<n>_GPI10 | SD5_CLK | SD demodulator clock channel 5 |
PRG<k>_PRU<n>_GPI11 | SD5_D | SD demodulator data channel 5 |
PRG<k>_PRU<n>_GPI12 | SD6_CLK | SD demodulator clock channel 6 |
PRG<k>_PRU<n>_GPI13 | SD6_D | SD demodulator data channel 6 |
PRG<k>_PRU<n>_GPI14 | SD7_CLK | SD demodulator clock channel 7 |
PRG<k>_PRU<n>_GPI15 | SD7_D | SD demodulator data channel 7 |
PRG<k>_PRU<n>_GPI16 | SD8_CLK | SD demodulator clock channel 8 |
PRG<k>_PRU<n>_GPI17 | SD8_D | SD demodulator data channel 8 |
PRG<k>_PRU<n>_GPI18 | - | |
PRG<k>_PRU<n>_GPI19 | - |
The PRG<k>_PRU0_GPI1 signal (muxed with SD0_D) can be used as SD_CLKOUT when PRU_ICSSG generates clock. This is a trade-off as PRU application will lose one SD channel. SD_CLKOUT needs to go through a clock generator chip if driving multiple sigma delta modulators and also be looped back into PRU_ICSSG as SD_CLKIN, typically pru_gpi16.
Note: To output the SD clock on PR<k>_PRU0_GPO1, this device requires that the PRU core be configured for both SD and shift out mode (ICSSG_GPCFG0_REG[29-26] PR1_PRU0_GP_MUX_SEL = 3h and ICSSG_GPCFG0_REG[14] PRU<n>_GPO_MODE = 1h). Be sure to configure the shift out mode's clock divisors before enabling shift out mode (ICSSG_GPCFG0_REG[14] PRU<n>_GPO_MODE = 1h). Additionally, the PRU_ICSSG0, PRU0 SD clock is routed to both PR0_PRU0_GPO1 and PR0_PRU1_GPO1. Figure 6-192 shows a block diagram of the Sigma Delta implementation. Full description of the PRU R30 and R31 registers are shown in Table 6-419 and Table 6-420.
Note: Each channel can independently be configured to use one of three external clock sources. Table 6-418 shows the clock source options, selectable through ICSSG_PRU0_SD_CLK_SEL_REGi[1-0] PRU0_SD_CLK_SELi (where n = 0 or 1 and i = 0 to 8).
PRU0_SD_CLK_SELi value | Clock Source |
---|---|
0 | pr<k>_pru<n>_sd8_clk |
1 | pr<k>_pru<n>_sd<i>_clk |
2 | pr<k>_pru<n>_sd0_clk for sd0, sd1, and sd2; pr<k>_pru<n>_sd3_clk for sd3, sd4, and sd5; pr<k>_pru<n>_sd6_clk for sd6, sd7, and sd8 |