Crate si4703

This is a platform agnostic Rust driver for the Si4702 and Si4703 FM radio turners (receivers) using the embedded-hal traits and I2C.

This driver allows you to:

• Enable/disable the device. See: enable().
• Mute/unmute. See: mute().
• Configure seek. See: configure_seek().
• Seek with/without STC interrupts. See: seek_with_stc_int_pin().
• Tune a frequency with/without STC interrupts. See: tune_with_stc_int_pin().
• Set volume. See: set_volume().
• Set band. See: set_band().
• Set channel spacing. See: set_channel_spacing().
• Set the GPIO1, GPIO2 and GPIO3 function/status. See: set_gpio1().
• Enable/disable softmute. See: enable_softmute().
• Enable/disable auto gain control. See: enable_auto_gain_control().
• Enable/disable oscillator. See: enable_oscillator().
• Enable/disable STC interrupts. See: enable_stc_interrupts().
• Enable/disable audio High-Z. See: enable_audio_high_z().
• Set de-emphasis. See: set_deemphasis().
• Set stereo to mono blend level. See: set_stereo_to_mono_blend_level().
• Set stereo/mono output mode. See: set_output_mode().
• Read output mode. See: output_mode().
• Read channel. See: channel().
• Read device ID. See: device_id().
• Read chip ID. See: chip_id().
• Reset and select I2C communication using several methods. See: reset_and_select_i2c_method1().
• RDS/RBDS (only on Si4703):
  • Enable/disable RDS. See: enable_rds().
  • Enable/disable RDS interrupts. See: enable_rds_interrupts().
  • Read whether a new RDS group is ready. See: rds_ready().
  • Read whether RDS is synchronized. See: rds_synchronized().
  • Read RDS data. See: rds_data().
  • Decode RDS radio text from RDS data. See: get_rds_radio_text().
  • Fill char array with decoded RDS radio text from RDS data. See: fill_with_rds_radio_text().

Introductory blog post

The devices

The Si4702/03-C19 extends Silicon Laboratories Si4700/Si4701 FM tuner family, and further increases the ease and attractiveness of adding FM radio reception to mobile devices through small size and board area, minimum component count, flexible programmability, and superior, proven performance.

The device offers significant programmability, and caters to the subjective nature of FM listeners and variable FM broadcast environments world-wide through a simplified programming interface and mature functionality.

The Si4703-C incorporates a digital processor for the European Radio Data System (RDS) and the US Radio Broadcast Data System (RBDS) including all required symbol decoding, block synchronization, error detection, and error correction functions.

RDS enables data such as station identification and song name to be displayed to the user. The Si4703-C offers a detailed RDS view and a standard view, allowing adopters to selectively choose granularity of RDS status, data, and block errors.

Datasheets:

• Si4702/Si4703

Further documentation:

• Si4700/01/02/03 Programmer’s Guide
• Using RDS/RBDS with the Si4701/03
• Si47xx Programming Guide

Usage (see also examples folder)

To use this driver, import this crate and an embedded_hal implementation, then instantiate the appropriate device. In the following examples an instance of the device Si4703 will be created as an example. An instance of the Si4702 device can be created with: Si4703::new_si4702(...).

Please find additional examples using hardware in this repository: driver-examples.

Seek a channel, listen for 5 seconds, then seek again

use embedded_hal::blocking::delay::DelayMs;
use linux_embedded_hal::{Delay, I2cdev, Pin};
use si4703::{
    reset_and_select_i2c_method1, ChannelSpacing, DeEmphasis, ErrorWithPin, SeekDirection,
    SeekMode, Si4703, Volume,
};

let mut delay = Delay {};
{
    // Reset and communication protocol selection must be done beforehand
    let mut sda = Pin::new(2);
    let mut rst = Pin::new(17);
    reset_and_select_i2c_method1(&mut rst, &mut sda, &mut delay).unwrap();
}
let dev = I2cdev::new("/dev/i2c-1").unwrap();
let mut radio = Si4703::new(dev);
radio.enable_oscillator().unwrap();
// Wait for the oscillator to stabilize
delay.delay_ms(500_u16);
radio.enable().unwrap();
// Wait for powerup
delay.delay_ms(110_u16);

radio.set_volume(Volume::Dbfsm28).unwrap();
radio.set_deemphasis(DeEmphasis::Us50).unwrap();
radio.set_channel_spacing(ChannelSpacing::Khz100).unwrap();
radio.unmute().unwrap();

// use STC interrupt pin method
let stc_int = Pin::new(27);
loop {
    match radio.seek_with_stc_int_pin(SeekMode::Wrap, SeekDirection::Up, &stc_int) {
        Err(nb::Error::WouldBlock) => {
            let channel = radio.channel().unwrap_or(-1.0);
            println!("Trying channel at {:1} MHz", channel);
        }
        Err(nb::Error::Other(ErrorWithPin::SeekFailed)) => {
            println!("Seek Failed");
        }
        Err(e) => {
            println!("Error: {:?}", e);
        }
        Ok(_) => {
            let channel = radio.channel().unwrap_or(-1.0);
            println!("Found channel at {:1} MHz", channel);
            delay.delay_ms(5000_u16); // listen for 5 seconds, then seek again
        }
    }
    delay.delay_ms(50_u8);
}

Structs

RdsBlockData

RDS block data

RdsData

RDS data data

RdsRadioText

RDS radio text

Si4703

Si4703 device driver

Enums

Band

Band

ChannelSpacing

Channel spacing

DeEmphasis

De-emphasis

Error

Errors in this crate

ErrorWithPin

Errors for operations involving I2C communication as well as interaction with pins

Gpio1Config

GPIO1 configuration

Gpio2Config

GPIO2 configuration

Gpio3Config

GPIO3 configuration

OutputMode

Output mode

RdsBlockErrors

RDS block errors

RdsMode

RDS mode

RdsRadioTextData

RDS radio text data

SeekDirection

Seek direction

SeekFmImpulseThreshold

Allowable number of FM impulses for a valid seek channel.

SeekMode

Seek mode

SeekSnrThreshold

Required channel SNR for a valid seek.

SoftmuteAttenuation

Softmute Attenuation

SoftmuteRate

Softmute Attack/Recover Rate

StereoToMonoBlendLevel

Stereo to mono blend level

TuneChannel

Tune channel frequency

Volume

Volume

Functions

fill_with_rds_radio_text

Fill char array with radio text with the RDS data.

get_rds_radio_text

Get radio text from RDS data.

reset_and_select_i2c_method1

Reset the device and select I2C communication (method 1, no GPIO3)

reset_and_select_i2c_method2

Reset the device and select I2C communication (method 2)

reset_and_select_i2c_method1_with_gpio3

Reset the device and select I2C communication (method 1 including GPIO3)