esp-hal 1.2.0

Bare-metal HAL for Espressif devices
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

//! PDM register programming for ESP32 (I2S hardware v1).

use super::{PdmConfig, PdmDataFormat, PdmError, PdmSlotMode, clock};
use crate::i2s::master::Info;

pub(crate) fn configure_pdm(i2s: &Info, config: &PdmConfig) -> Result<(), PdmError> {
    i2s.regs().conf2().modify(|_, w| {
        w.camera_en().clear_bit();
        w.lcd_en().clear_bit()
    });

    if let Some(tx) = &config.tx {
        configure_tx(i2s, tx)?;
    }
    if let Some(rx) = &config.rx {
        configure_rx(i2s, rx)?;
    }

    i2s.regs().fifo_conf().modify(|_, w| w.dscr_en().set_bit());
    i2s.regs().pd_conf().modify(|_, w| {
        w.fifo_force_pu().set_bit();
        w.fifo_force_pd().clear_bit()
    });

    Ok(())
}

fn configure_tx(i2s: &Info, config: &super::PdmTxConfig) -> Result<(), PdmError> {
    if !i2s.pdm_tx {
        return Err(PdmError::UnsupportedInstance);
    }

    let pcm = config.slot.data_format == PdmDataFormat::Pcm;
    let clock = clock::calculate_tx_clock(&config.clock, pcm)?;
    i2s.set_clock(clock.dividers);

    let is_mono = config.slot.slot_mode == PdmSlotMode::Mono;
    let regs = i2s.regs();

    regs.conf().modify(|_, w| {
        w.tx_msb_shift().clear_bit();
        w.tx_mono().bit(is_mono);
        w.tx_right_first().clear_bit();
        w.tx_msb_right().clear_bit()
    });

    regs.sample_rate_conf()
        .modify(|_, w| unsafe { w.tx_bits_mod().bits(16) });

    regs.fifo_conf().modify(|_, w| unsafe {
        w.tx_fifo_mod().bits(if is_mono { 1 } else { 0 });
        w.tx_fifo_mod_force_en().set_bit()
    });

    if pcm {
        regs.pdm_conf().modify(|_, w| unsafe {
            w.tx_pdm_prescale().bits(config.slot.sd_prescale);
            w.tx_pdm_sigmadelta_in_shift()
                .bits(config.slot.sd_scale.to_register());
            w.tx_pdm_hp_in_shift()
                .bits(config.slot.hp_scale.to_register());
            w.tx_pdm_lp_in_shift()
                .bits(config.slot.lp_scale.to_register());
            w.tx_pdm_sinc_in_shift()
                .bits(config.slot.sinc_scale.to_register())
        });

        if clock.over_sample_ratio > 0 {
            regs.pdm_conf()
                .modify(|_, w| unsafe { w.tx_pdm_sinc_osr2().bits(clock.over_sample_ratio as u8) });
        }

        regs.pdm_freq_conf().modify(|_, w| unsafe {
            w.tx_pdm_fp().bits(config.clock.up_sample_fp as u16);
            w.tx_pdm_fs().bits(config.clock.up_sample_fs as u16)
        });
    }

    let slot_mask = config.slot.slot_mask.bits();
    regs.conf_chan().modify(|_, w| unsafe {
        // Mono uses 3/4/1, stereo uses 1/2/0.
        let chan_mod = if is_mono {
            match slot_mask {
                0b01 => 3u8,
                0b10 => 4u8,
                _ => 1u8,
            }
        } else {
            match slot_mask {
                0b01 => 1u8,
                0b10 => 2u8,
                _ => 0u8,
            }
        };
        w.tx_chan_mod().bits(chan_mod)
    });

    regs.pdm_conf().modify(|_, w| {
        w.tx_pdm_en().set_bit();
        w.pcm2pdm_conv_en().bit(pcm)
    });

    Ok(())
}

fn configure_rx(i2s: &Info, config: &super::PdmRxConfig) -> Result<(), PdmError> {
    if !i2s.pdm_rx {
        return Err(PdmError::UnsupportedInstance);
    }

    let pcm = config.slot.data_format == PdmDataFormat::Pcm;
    #[cfg(i2s_supports_pdm2pcm)]
    let pdm2pcm = pcm;
    #[cfg(not(i2s_supports_pdm2pcm))]
    let pdm2pcm = false;

    let slot_mask = config.slot.slot_mask.bits();
    let clock = clock::calculate_rx_clock(&config.clock, pcm, slot_mask)?;
    i2s.set_clock(clock.dividers);

    let is_mono = config.slot.slot_mode == PdmSlotMode::Mono;
    let regs = i2s.regs();

    regs.conf().modify(|_, w| {
        w.rx_msb_shift().clear_bit();
        w.rx_mono().bit(is_mono);
        w.rx_right_first().clear_bit();
        w.rx_msb_right().clear_bit()
    });

    regs.sample_rate_conf()
        .modify(|_, w| unsafe { w.rx_bits_mod().bits(16) });

    regs.fifo_conf().modify(|_, w| unsafe {
        w.rx_fifo_mod().bits(if is_mono { 1 } else { 0 });
        w.rx_fifo_mod_force_en().set_bit()
    });

    regs.conf_chan().modify(|_, w| unsafe {
        // PDM RX always uses 1/2/0, not TDM mono 3/4/0.
        let chan_mod = match slot_mask {
            0b01 => 1u8,
            0b10 => 2u8,
            _ => 0u8,
        };
        w.rx_chan_mod().bits(chan_mod)
    });

    regs.pdm_conf().modify(|_, w| {
        w.rx_pdm_en().set_bit();
        w.pdm2pcm_conv_en().bit(pdm2pcm);
        w.rx_pdm_sinc_dsr_16_en()
            .bit(config.clock.downsample_rate == super::PdmDownsampleRate::Dsr16s)
    });

    Ok(())
}