BL702/704/706 Reference Manual
sequence, and the modulation order is {A0},{A1},{A2},...
If gpdac_dma_format is 1, the high 16 bits of the data transferred into gpdac_dma_wdata by DMA are modulated in
Channel B, and the low 16 bits are modulated in Channel A. The modulation sequence is {B0,A0},{B1,A1},{B2,A2},....
This feature is very useful in stereo playback.
If gpdac_dma_format is 2, the data transferred by DMA into gpdac_dma_wdata is all modulated in Channel A, but the
order of modulation is {A1,A0},{A3,A2},{A5,A4},...
DAC external reference voltage selection
The user can select external reference voltage or internal reference voltage by configuring gpdac_ref_sel (0x40000308[8]).
If the internal reference voltage is selected, the configuration is shown in the following table.
Table 5.1: Internal reference voltage
gpdac_a_rng
gpdac_ref_sel Output range
00 0 0.2-1
01/10 0 0.225-1.425
11 0 0.2-1.8
If you choose an external reference voltage, please connect the external voltage to the fixed GPIO7.
5.4 Register description
Name
Description
gpdac_config GPDAC configuration
gpdac_dma_config GPDAC dma configuration
gpdac_dma_wdata GPDAC dma write data
gpdac_ctrl GPDAC control
gpdac_actrl GPDAC channelA control
gpdac_bctrl GPDAC channelB control
gpdac_data GPDAC data
BL702/704/706 Reference Manual 113/ 375
@2021 Bouffalo Lab
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