enhance(spi): impl half-duplex spi

Author: andelf

examples/hpm5300evk/src/bin/qspi.rs

@@ -282,14 +282,12 @@ fn main() -> ! {
     // PA10
     let mut led = Output::new(p.PA10, Level::Low, Speed::Fast);
 
-    let spi_config = Config {
-        frequency: Hertz(40_000_000),
-        mode: MODE_0,
-        timing: Timings {
-            cs2sclk: hpm_hal::spi::Cs2Sclk::_1HalfSclk,
-            csht: hpm_hal::spi::CsHighTime::_8HalfSclk,
-        },
-        ..Default::default()
+    let mut spi_config = Config::default();
+    spi_config.frequency = Hertz(40_000_000);
+    spi_config.mode = MODE_0;
+    spi_config.timing = Timings {
+        cs2sclk: hpm_hal::spi::Cs2Sclk::_1HalfSclk,
+        csht: hpm_hal::spi::CsHighTime::_8HalfSclk,
     };
 
     let spi: hal::spi::Spi<'_, Blocking> =

src/spi/mod.rs

@@ -142,6 +142,8 @@ pub struct Config {
     pub frequency: Hertz,
     /// Timings
     pub timing: Timings,
+    /// Half duplex mode, only MOSI is used.
+    pub half_duplex: bool,
 }
 
 impl Default for Config {
@@ -151,6 +153,7 @@ impl Default for Config {
             mode: MODE_0,
             frequency: Hertz(10_000_000),
             timing: Timings::default(),
+            half_duplex: false,
         }
     }
 }
@@ -253,6 +256,36 @@ impl<'d> Spi<'d, Blocking> {
         )
     }
 
+    pub fn new_blocking_half_duplex<T: Instance>(
+        peri: impl Peripheral<P = T> + 'd,
+        sclk: impl Peripheral<P = impl SclkPin<T>> + 'd,
+        mosi: impl Peripheral<P = impl MosiPin<T>> + 'd,
+        mut config: Config,
+    ) -> Self {
+        into_ref!(sclk, mosi);
+
+        T::add_resource_group(0);
+
+        mosi.set_as_alt(mosi.alt_num());
+        sclk.ioc_pad().func_ctl().modify(|w| {
+            w.set_alt_select(sclk.alt_num());
+            w.set_loop_back(true);
+        });
+        config.half_duplex = true;
+
+        Self::new_inner(
+            peri,
+            Some(sclk.map_into()),
+            Some(mosi.map_into()),
+            None,
+            None,
+            None,
+            None,
+            None,
+            config,
+        )
+    }
+
     pub fn new_blocking_rxonly<T: Instance>(
         peri: impl Peripheral<P = T> + 'd,
         sclk: impl Peripheral<P = impl SclkPin<T>> + 'd,
@@ -406,6 +439,39 @@ impl<'d> Spi<'d, Async> {
         )
     }
 
+    pub fn new_half_duplex<T: Instance>(
+        peri: impl Peripheral<P = T> + 'd,
+        sclk: impl Peripheral<P = impl SclkPin<T>> + 'd,
+        mosi: impl Peripheral<P = impl MosiPin<T>> + 'd,
+        tx_dma: impl Peripheral<P = impl TxDma<T>> + 'd,
+        rx_dma: impl Peripheral<P = impl RxDma<T>> + 'd,
+        mut config: Config,
+    ) -> Self {
+        into_ref!(sclk, mosi);
+
+        T::add_resource_group(0);
+
+        mosi.set_as_alt(mosi.alt_num());
+        sclk.ioc_pad().func_ctl().modify(|w| {
+            w.set_alt_select(sclk.alt_num());
+            w.set_loop_back(true);
+        });
+
+        config.half_duplex = true;
+
+        Self::new_inner(
+            peri,
+            Some(sclk.map_into()),
+            Some(mosi.map_into()),
+            None,
+            None,
+            None,
+            new_dma!(tx_dma),
+            new_dma!(rx_dma),
+            config,
+        )
+    }
+
     pub fn new_rxonly<T: Instance>(
         peri: impl Peripheral<P = T> + 'd,
         sclk: impl Peripheral<P = impl SclkPin<T>> + 'd,
@@ -690,7 +756,11 @@ impl<'d, M: PeriMode> Spi<'d, M> {
             // 32 bit data length only works when the data is 32bit aligned
             w.set_datalen(<u8 as SealedWord>::CONFIG);
             w.set_datamerge(false);
-            w.set_mosibidir(false);
+            if config.half_duplex {
+                w.set_mosibidir(true);
+            } else {
+                w.set_mosibidir(false);
+            }
             w.set_lsb(config.bit_order == BitOrder::LsbFirst);
             w.set_slvmode(false); // default master mode
             w.set_cpha(cpha);