Allow audio sampling rate of 96 kHz

Signed-off-by: Petr Horacek <[email protected]>

CHANGELOG.md

@@ -6,6 +6,8 @@ backwards compatibility.
 
 ## Unreleased
 
+* Allow audio sampling rate of 96 kHz.
+
 ## 0.8.0
 
 * **Breaking** Remove logging abstractions from the crate.

Cargo.toml

@@ -45,6 +45,7 @@ stm32h7xx-hal = { version = "0.14", features = [ "stm32h750v", "rt", "revision_v
 seed = []
 seed_1_1 = [ "num_enum" ]
 patch_sm = [ "num_enum" ]
+sampling_rate_96khz = []
 
 [[example]]
 name = "blinky"

Makefile

@@ -13,6 +13,7 @@ format:
 clippy:
 	cargo clippy --all --examples --features seed -- -D warnings
 	cargo clippy --all --examples --features seed_1_1 -- -D warnings
+	cargo clippy --all --examples --features seed_1_1,sampling_rate_96khz -- -D warnings
 	cargo clippy --all --examples --features patch_sm -- -D warnings
 	cargo clippy --all --examples --features seed -- -D warnings
 

README.md

@@ -23,6 +23,11 @@ Select the board by using its respective feature.
 make flash WHAT=blinky BOARD=seed_1_1
 ```
 
+# Sampling rate
+
+By default, the audio sampling rate is set to 48 kHz. This can be increased to
+96 kHz by enabling the `sampling_rate_96khz` feature.
+
 # API stability
 
 I am still trying to figure out a good API for the project. Expect it to change.

src/audio/codec/wm8731.rs

@@ -74,6 +74,11 @@ enum Register {
     RESET = 0x0F,
 }
 
+#[cfg(not(feature = "sampling_rate_96khz"))]
+const SAMPLING_RATE: u8 = 0x00; // 48 kHz
+#[cfg(feature = "sampling_rate_96khz")]
+const SAMPLING_RATE: u8 = 0x07; // 96 kHz
+
 const REGISTER_CONFIG: &[(Register, u8)] = &[
     // Reset Codec.
     (Register::RESET, 0x00),
@@ -91,7 +96,7 @@ const REGISTER_CONFIG: &[(Register, u8)] = &[
     // Configure digital format.
     (Register::IFACE, 0x09),
     // Set samplerate.
-    (Register::SRATE, 0x00),
+    (Register::SRATE, SAMPLING_RATE),
     (Register::ACTIVE, 0x00),
     (Register::ACTIVE, 0x01),
 ];

src/audio/mod.rs

@@ -12,4 +12,8 @@ pub use interface::{Block, Interface};
 pub const BLOCK_LENGTH: usize = 32; // 32 samples
 pub const HALF_DMA_BUFFER_LENGTH: usize = BLOCK_LENGTH * 2; // 2 channels
 pub const DMA_BUFFER_LENGTH: usize = HALF_DMA_BUFFER_LENGTH * 2; // 2 half-blocks
+
+#[cfg(not(feature = "sampling_rate_96khz"))]
 pub const FS: time::Hertz = time::Hertz::from_raw(48_000);
+#[cfg(feature = "sampling_rate_96khz")]
+pub const FS: time::Hertz = time::Hertz::from_raw(96_000);

src/lib.rs

@@ -16,6 +16,12 @@
 //!
 //! Select the board by using its respective feature.
 //!
+//! # Sampling rate
+//!
+//! By default, the audio sampling rate is set to 48 kHz. This can be increased to
+//! 96 kHz by enabling the `sampling_rate_96khz` feature.
+//!
+//!
 //! # API stability
 //!
 //! I am still trying to figure out a good API for the project. Expect it to change.