From 8790a7ce049f06d2bb356cb649714c29624c20f1 Mon Sep 17 00:00:00 2001
From: Thomas Kolb <cfr34k-git@tkolb.de>
Date: Wed, 4 Jan 2023 13:30:30 +0100
Subject: [PATCH] Trying to move the ADC reader code to a separate function

---
 src/main.rs | 36 ++++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 2c88e6d..6c45033 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -54,6 +54,27 @@ const HIGH: u16 = 25000;
 /// if your board has a different frequency
 const XTAL_FREQ_HZ: u32 = 12_000_000u32;
 
+fn get_adc_channel_blocking<S, D, const DS: u8, E>(dma: &hal::dma::Channels, spi: &mut rp2040_hal::Spi<S, D, DS>, cs_pin: &dyn embedded_hal::digital::v2::OutputPin<Error = E>) -> u16
+where
+    S: hal::spi::State,
+    D: hal::spi::SpiDevice,
+    E: core::fmt::Debug
+{
+    let mut tx_buf: [u8; 3] = [0x06, 0x40, 0x00];
+    let mut rx_buf: [u8; 3] = [0; 3];
+
+    // clear chip select
+    cs_pin.set_low().unwrap();
+
+    // Use BidirectionalConfig to simultaneously write to spi from tx_buf and read into rx_buf
+    let transfer = bidirectional::Config::new((dma.ch0, dma.ch1), &tx_buf, spi, &rx_buf).start();
+    // Wait for both DMA channels to finish
+    let ((_ch0, _ch1), tx_buf, _spi, rx_buf) = transfer.wait();
+    cs_pin.set_high().unwrap();
+
+    (((rx_buf[1] & 0x0F) as u16) << 8) | rx_buf[2] as u16
+}
+
 /// Entry point to our bare-metal application.
 ///
 /// The `#[rp2040_hal::entry]` macro ensures the Cortex-M start-up code calls this function
@@ -170,19 +191,10 @@ fn main() -> ! {
     let dma = pac.DMA.split(&mut pac.RESETS);
 
     // Use DMA to read ADC (0xC0 in byte 1 is the channel mask)
-    let tx_buf = singleton!(: [u8; 3] = [0x06, 0x40, 0x00]).unwrap();
-    let rx_buf = singleton!(: [u8; 3] = [0; 3]).unwrap();
+    //let tx_buf = singleton!(: [u8; 3] = [0x06, 0x40, 0x00]).unwrap();
+    //let rx_buf = singleton!(: [u8; 3] = [0; 3]).unwrap();
 
-    // clear chip select
-    spi_cs.set_low().unwrap();
-
-    // Use BidirectionalConfig to simultaneously write to spi from tx_buf and read into rx_buf
-    let transfer = bidirectional::Config::new((dma.ch0, dma.ch1), tx_buf, spi, rx_buf).start();
-    // Wait for both DMA channels to finish
-    let ((_ch0, _ch1), tx_buf, _spi, rx_buf) = transfer.wait();
-    spi_cs.set_high().unwrap();
-
-    let adc_value = (((rx_buf[1] & 0x0F) as u16) << 8) | rx_buf[2] as u16;
+    let adc_value = get_adc_channel_blocking(&dma, &mut spi, &spi_cs);
 
     {
         let data: String<16> = String::from(adc_value);