Spi slave mode

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Spi Slave mode
 - Reexport gpio pins to `gpio` mod
 - Added the ability to specify the word size (8 or 9 bits) for `Serial` (USART). When using parity, the parity bit is included in the number of bits of the word.
 - `blocking::serial::Write` for `Tx` and `Serial`. `core::fmt::Write` for `Serial`

examples/spi-slave.rs

@@ -0,0 +1,154 @@
+//! SPI slave mode test
+//!
+//! spi1 master <-> spi2 slave
+//! PA5 <-SCK-> PB13
+//! PA6 <-MISO-> PB14
+//! PA7 <-MOSI-> PB15
+
+#![allow(clippy::empty_loop)]
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::entry;
+use panic_halt as _;
+
+use cortex_m::{asm, singleton};
+use embedded_hal::spi::{Mode, Phase, Polarity};
+pub const MODE: Mode = Mode {
+    phase: Phase::CaptureOnSecondTransition,
+    polarity: Polarity::IdleHigh,
+};
+
+use stm32f1xx_hal::{
+    gpio::{
+        gpiob::{PB13, PB14, PB15},
+        Alternate, Floating, Input, PushPull,
+    },
+    pac::{self, interrupt, Peripherals, SPI2},
+    prelude::*,
+    spi::{Event, Slave, Spi, Spi2NoRemap},
+};
+
+type SlaveSpi = Spi<
+    SPI2,
+    Spi2NoRemap,
+    (
+        PB13<Input<Floating>>,
+        PB14<Alternate<PushPull>>,
+        PB15<Input<Floating>>,
+    ),
+    u8,
+    Slave,
+>;
+
+static mut SPI2SLAVE: Option<SlaveSpi> = None;
+
+#[entry]
+fn main() -> ! {
+    let dp = Peripherals::take().unwrap();
+
+    let mut flash = dp.FLASH.constrain();
+    let rcc = dp.RCC.constrain();
+
+    let clocks = rcc.cfgr.freeze(&mut flash.acr);
+
+    let mut afio = dp.AFIO.constrain();
+    let mut gpioa = dp.GPIOA.split();
+    let mut gpiob = dp.GPIOB.split();
+
+    // SPI1
+    let sck = gpioa.pa5.into_alternate_push_pull(&mut gpioa.crl);
+    let miso = gpioa.pa6;
+    let mosi = gpioa.pa7.into_alternate_push_pull(&mut gpioa.crl);
+
+    let spi1 = Spi::spi1(
+        dp.SPI1,
+        (sck, miso, mosi),
+        &mut afio.mapr,
+        MODE,
+        10.kHz(),
+        clocks,
+    );
+
+    // SPI2
+    let sck = gpiob.pb13;
+    let miso = gpiob.pb14.into_alternate_push_pull(&mut gpiob.crh);
+    let mosi = gpiob.pb15;
+
+    let spi2 = Spi::spi2_slave(dp.SPI2, (sck, miso, mosi), MODE);
+
+    // Set up the DMA device
+    let dma = dp.DMA1.split();
+
+    let master_spi_dma = spi1.with_rx_tx_dma(dma.2, dma.3);
+    let slave_spi_dma = spi2.with_rx_tx_dma(dma.4, dma.5);
+
+    let master_buf = singleton!(: [u8; 12] = [0; 12]).unwrap();
+    let slave_buf = singleton!(: [u8; 12] = [0; 12]).unwrap();
+
+    // Make sure the buffers are the same length
+    let slave_transfer = slave_spi_dma.read_write(slave_buf, b"hello,master");
+    let master_transfer = master_spi_dma.read_write(master_buf, b"hello, slave");
+
+    let (buffer, spi1_dma) = master_transfer.wait();
+    let (_buffer, spi2_dma) = slave_transfer.wait();
+
+    asm::bkpt();
+
+    // test SPI with interrupts
+    let (mut spi2, _, _) = spi2_dma.release();
+
+    spi2.listen(Event::Rxne);
+    spi2.listen(Event::Txe);
+    spi2.listen(Event::Error);
+
+    cortex_m::interrupt::free(|_| unsafe {
+        SPI2SLAVE.replace(spi2);
+    });
+
+    unsafe {
+        cortex_m::peripheral::NVIC::unmask(pac::Interrupt::SPI2);
+    }
+
+    let master_transfer = spi1_dma.read_write(buffer.0, buffer.1);
+    let (_buffer, _spi1_dma) = master_transfer.wait();
+
+    loop {}
+}
+
+const R_BUFFER_LEN: usize = 16;
+static mut R_BUFFER: &mut [u8; R_BUFFER_LEN] = &mut [0; R_BUFFER_LEN];
+static mut RIDX: usize = 0;
+
+const W_BUFFER_LEN: usize = 3;
+static W_BUFFER: &[u8; W_BUFFER_LEN] = &[1, 2, 3];
+static mut WIDX: usize = 0;
+
+#[interrupt]
+unsafe fn SPI2() {
+    cortex_m::interrupt::free(|_| {
+        if let Some(spi2) = SPI2SLAVE.as_mut() {
+            if spi2.is_overrun() {
+                // mcu processing speed is not enough
+                asm::bkpt();
+            }
+            if spi2.is_rx_not_empty() {
+                if let Ok(w) = nb::block!(spi2.read()) {
+                    R_BUFFER[RIDX] = w;
+                    RIDX += 1;
+                    if RIDX >= R_BUFFER_LEN - 1 {
+                        RIDX = 0;
+                    }
+                }
+            }
+            if spi2.is_tx_empty() {
+                if let Ok(()) = nb::block!(spi2.send(W_BUFFER[WIDX])) {
+                    WIDX += 1;
+                    if WIDX >= W_BUFFER_LEN {
+                        WIDX = 0;
+                    }
+                }
+            }
+        }
+    })
+}