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)