Created basic lib for AD5940.

src/ad5940.rs

@@ -0,0 +1,51 @@
+use embassy_stm32::{gpio::Output, mode::Blocking, spi::Spi};
+
+pub struct AD5940 {
+    spi: Spi<'static, Blocking>,
+    cs: Output<'static>,
+}
+
+impl AD5940 {
+    pub fn new(spi: Spi<'static, Blocking>, cs: Output<'static>) -> Self {
+        AD5940 { spi, cs }
+    }
+
+    fn read_reg_16(&mut self, address: u16) -> Result<u16, embassy_stm32::spi::Error> {
+        let addr_bytes = address.to_be_bytes();
+
+        // Write address command
+        self.cs.set_low();
+        self.spi.blocking_write(&[Command::SPICMD_SETADDR as u8])?;
+        self.spi.blocking_write(&addr_bytes)?;
+        self.cs.set_high();
+
+        // Read command
+        self.cs.set_low();
+        self.spi.blocking_write(&[Command::SPICMD_READREG as u8])?;
+
+        let mut data = [0u8; 3]; // First byte dummy, then two data bytes
+        self.spi.blocking_read(&mut data)?;
+        self.cs.set_high();
+
+        Ok(u16::from_be_bytes([data[1], data[2]]))
+    }
+
+    pub fn get_chipid(&mut self) -> Result<u16, embassy_stm32::spi::Error> {
+        self.read_reg_16(Register::CHIPID as u16)
+    }
+}
+
+#[allow(dead_code)]
+#[allow(non_camel_case_types)]
+enum Command {
+    SPICMD_SETADDR = 0x20,
+    SPICMD_READREG = 0x6D,
+    SPICMD_WRITEREG = 0x2D,
+    SPICMD_READFIFO = 0x5F,
+}
+
+#[allow(non_camel_case_types)]
+#[repr(u16)]
+enum Register {
+    CHIPID = 0x0000_0404, // Changed from u32 to u16, as expected by SPI write
+}