From 1e23b8114bb1f4b9e092bc50b3cfe4bd2f7ebdb6 Mon Sep 17 00:00:00 2001
From: i509VCB <git@i509.me>
Date: Sun, 6 Apr 2025 21:13:49 -0500
Subject: mspm0: add uart tests

This also fixes a bug in the uart clock calculation where it could select an oversampling faster than what the hardware is providing.
---
 tests/mspm0/src/bin/uart.rs | 83 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 tests/mspm0/src/bin/uart.rs

(limited to 'tests/mspm0/src')

diff --git a/tests/mspm0/src/bin/uart.rs b/tests/mspm0/src/bin/uart.rs
new file mode 100644
index 000000000..458129d44
--- /dev/null
+++ b/tests/mspm0/src/bin/uart.rs
@@ -0,0 +1,83 @@
+#![no_std]
+#![no_main]
+
+#[cfg(feature = "mspm0g3507")]
+teleprobe_meta::target!(b"lp-mspm0g3507");
+
+use defmt::{assert_eq, unwrap, *};
+use embassy_executor::Spawner;
+use embassy_mspm0::mode::Blocking;
+use embassy_mspm0::uart::{ClockSel, Config, Error, Uart};
+use {defmt_rtt as _, panic_probe as _};
+
+fn read<const N: usize>(uart: &mut Uart<'_, Blocking>) -> Result<[u8; N], Error> {
+    let mut buf = [255; N];
+    uart.blocking_read(&mut buf)?;
+    Ok(buf)
+}
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_mspm0::init(Default::default());
+    info!("Hello World!");
+
+    // TODO: Allow creating a looped-back UART (so pins are not needed).
+    // Do not select default UART since the virtual COM port is attached to UART0.
+    #[cfg(feature = "mspm0g3507")]
+    let (mut tx, mut rx, mut uart) = (p.PA8, p.PA9, p.UART1);
+
+    const MFCLK_BUAD_RATES: &[u32] = &[1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200];
+
+    for &rate in MFCLK_BUAD_RATES {
+        info!("{} baud using MFCLK", rate);
+
+        let mut config = Config::default();
+        // MSPM0 hardware supports a loopback mode to allow self test.
+        config.loop_back_enable = true;
+        config.baudrate = rate;
+
+        let mut uart = unwrap!(Uart::new_blocking(
+            uart.reborrow(),
+            rx.reborrow(),
+            tx.reborrow(),
+            config
+        ));
+
+        // We can't send too many bytes, they have to fit in the FIFO.
+        // This is because we aren't sending+receiving at the same time.
+
+        let data = [0xC0, 0xDE];
+        unwrap!(uart.blocking_write(&data));
+        assert_eq!(unwrap!(read(&mut uart)), data);
+    }
+
+    // 9600 is the maximum possible value for 32.768 kHz.
+    const LFCLK_BAUD_RATES: &[u32] = &[1200, 2400, 4800, 9600];
+
+    for &rate in LFCLK_BAUD_RATES {
+        info!("{} baud using LFCLK", rate);
+
+        let mut config = Config::default();
+        // MSPM0 hardware supports a loopback mode to allow self test.
+        config.loop_back_enable = true;
+        config.baudrate = rate;
+        config.clock_source = ClockSel::LfClk;
+
+        let mut uart = expect!(Uart::new_blocking(
+            uart.reborrow(),
+            rx.reborrow(),
+            tx.reborrow(),
+            config,
+        ));
+
+        // We can't send too many bytes, they have to fit in the FIFO.
+        // This is because we aren't sending+receiving at the same time.
+
+        let data = [0xC0, 0xDE];
+        unwrap!(uart.blocking_write(&data));
+        assert_eq!(unwrap!(read(&mut uart)), data);
+    }
+
+    info!("Test OK");
+    cortex_m::asm::bkpt();
+}
-- 
cgit