Merge #1430

1430: Handle SUBGHZSPI as async r=lulf a=ceekdee

For STM32WL, simplify configuration for the use of SUBGHZSPI to perform LoRa operations.  Use Rx/Tx DMA on SPI to enable async functionality.

Co-authored-by: ceekdee <taigatensor@gmail.com>
Co-authored-by: Chuck Davis <taigatensor@gmail.com>

embassy-stm32/src/spi/mod.rs

@@ -195,15 +195,20 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
     }
 
     /// Useful for on chip peripherals like SUBGHZ which are hardwired.
-    /// The bus can optionally be exposed externally with `Spi::new()` still.
     #[allow(dead_code)]
     pub fn new_subghz(
         peri: impl Peripheral<P = T> + 'd,
         txdma: impl Peripheral<P = Tx> + 'd,
         rxdma: impl Peripheral<P = Rx> + 'd,
-        freq: Hertz,
+        pclk3_freq: u32,
-        config: Config,
     ) -> Self {
+        // see RM0453 rev 1 section 7.2.13 page 291
+        // The SUBGHZSPI_SCK frequency is obtained by PCLK3 divided by two.
+        // The SUBGHZSPI_SCK clock maximum speed must not exceed 16 MHz.
+        let freq = Hertz(core::cmp::min(pclk3_freq / 2, 16_000_000));
+        let mut config = Config::default();
+        config.mode = MODE_0;
+        config.bit_order = BitOrder::MsbFirst;
         Self::new_inner(peri, None, None, None, txdma, rxdma, freq, config)
     }
 

examples/stm32wl/src/bin/lora_lorawan.rs

@@ -7,17 +7,14 @@
 #![allow(incomplete_features)]
 
 use defmt::info;
-use embassy_embedded_hal::adapter::BlockingAsync;
 use embassy_executor::Spawner;
 use embassy_lora::iv::Stm32wlInterfaceVariant;
 use embassy_lora::LoraTimer;
-use embassy_stm32::dma::NoDma;
 use embassy_stm32::gpio::{Level, Output, Pin, Speed};
 use embassy_stm32::peripherals::SUBGHZSPI;
 use embassy_stm32::rcc::low_level::RccPeripheral;
 use embassy_stm32::rng::Rng;
-use embassy_stm32::spi::{BitOrder, Config as SpiConfig, Spi, MODE_0};
+use embassy_stm32::spi::Spi;
-use embassy_stm32::time::Hertz;
 use embassy_stm32::{interrupt, into_ref, pac, Peripheral};
 use embassy_time::Delay;
 use lora_phy::mod_params::*;
@@ -33,19 +30,14 @@ const LORAWAN_REGION: region::Region = region::Region::EU868; // warning: set th
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
     let mut config = embassy_stm32::Config::default();
-    config.rcc.mux = embassy_stm32::rcc::ClockSrc::HSI16;
+    config.rcc.mux = embassy_stm32::rcc::ClockSrc::HSE32;
-    config.rcc.enable_lsi = true;
+    config.rcc.enable_lsi = true; // enable RNG
     let p = embassy_stm32::init(config);
 
     unsafe { pac::RCC.ccipr().modify(|w| w.set_rngsel(0b01)) }
 
-    let clk = Hertz(core::cmp::min(SUBGHZSPI::frequency().0 / 2, 16_000_000));
+    let pclk3_freq = SUBGHZSPI::frequency().0;
-    let mut spi_config = SpiConfig::default();
+    let spi = Spi::new_subghz(p.SUBGHZSPI, p.DMA1_CH1, p.DMA1_CH2, pclk3_freq);
-    spi_config.mode = MODE_0;
-    spi_config.bit_order = BitOrder::MsbFirst;
-    let spi = Spi::new_subghz(p.SUBGHZSPI, NoDma, NoDma, clk, spi_config);
-
-    let spi = BlockingAsync::new(spi);
 
     let irq = interrupt::take!(SUBGHZ_RADIO);
     into_ref!(irq);

examples/stm32wl/src/bin/lora_p2p_receive.rs

@@ -7,15 +7,12 @@
 #![allow(incomplete_features)]
 
 use defmt::info;
-use embassy_embedded_hal::adapter::BlockingAsync;
 use embassy_executor::Spawner;
 use embassy_lora::iv::Stm32wlInterfaceVariant;
-use embassy_stm32::dma::NoDma;
 use embassy_stm32::gpio::{Level, Output, Pin, Speed};
 use embassy_stm32::peripherals::SUBGHZSPI;
 use embassy_stm32::rcc::low_level::RccPeripheral;
-use embassy_stm32::spi::{BitOrder, Config as SpiConfig, Spi, MODE_0};
+use embassy_stm32::spi::Spi;
-use embassy_stm32::time::Hertz;
 use embassy_stm32::{interrupt, into_ref, Peripheral};
 use embassy_time::{Delay, Duration, Timer};
 use lora_phy::mod_params::*;
@@ -31,13 +28,8 @@ async fn main(_spawner: Spawner) {
     config.rcc.mux = embassy_stm32::rcc::ClockSrc::HSE32;
     let p = embassy_stm32::init(config);
 
-    let clk = Hertz(core::cmp::min(SUBGHZSPI::frequency().0 / 2, 16_000_000));
+    let pclk3_freq = SUBGHZSPI::frequency().0;
-    let mut spi_config = SpiConfig::default();
+    let spi = Spi::new_subghz(p.SUBGHZSPI, p.DMA1_CH1, p.DMA1_CH2, pclk3_freq);
-    spi_config.mode = MODE_0;
-    spi_config.bit_order = BitOrder::MsbFirst;
-    let spi = Spi::new_subghz(p.SUBGHZSPI, NoDma, NoDma, clk, spi_config);
-
-    let spi = BlockingAsync::new(spi);
 
     let irq = interrupt::take!(SUBGHZ_RADIO);
     into_ref!(irq);

examples/stm32wl/src/bin/lora_p2p_send.rs

@@ -7,15 +7,12 @@
 #![allow(incomplete_features)]
 
 use defmt::info;
-use embassy_embedded_hal::adapter::BlockingAsync;
 use embassy_executor::Spawner;
 use embassy_lora::iv::Stm32wlInterfaceVariant;
-use embassy_stm32::dma::NoDma;
 use embassy_stm32::gpio::{Level, Output, Pin, Speed};
 use embassy_stm32::peripherals::SUBGHZSPI;
 use embassy_stm32::rcc::low_level::RccPeripheral;
-use embassy_stm32::spi::{BitOrder, Config as SpiConfig, Spi, MODE_0};
+use embassy_stm32::spi::Spi;
-use embassy_stm32::time::Hertz;
 use embassy_stm32::{interrupt, into_ref, Peripheral};
 use embassy_time::Delay;
 use lora_phy::mod_params::*;
@@ -31,13 +28,8 @@ async fn main(_spawner: Spawner) {
     config.rcc.mux = embassy_stm32::rcc::ClockSrc::HSE32;
     let p = embassy_stm32::init(config);
 
-    let clk = Hertz(core::cmp::min(SUBGHZSPI::frequency().0 / 2, 16_000_000));
+    let pclk3_freq = SUBGHZSPI::frequency().0;
-    let mut spi_config = SpiConfig::default();
+    let spi = Spi::new_subghz(p.SUBGHZSPI, p.DMA1_CH1, p.DMA1_CH2, pclk3_freq);
-    spi_config.mode = MODE_0;
-    spi_config.bit_order = BitOrder::MsbFirst;
-    let spi = Spi::new_subghz(p.SUBGHZSPI, NoDma, NoDma, clk, spi_config);
-
-    let spi = BlockingAsync::new(spi);
 
     let irq = interrupt::take!(SUBGHZ_RADIO);
     into_ref!(irq);