Add dummy code to read from the external ADC

Cargo.lock

@@ -8,6 +8,15 @@ version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8da52d66c7071e2e3fa2a1e5c6d088fec47b593032b254f5e980de8ea54454d6"
 
+[[package]]
+name = "atomic-polyfill"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3ff7eb3f316534d83a8a2c3d1674ace8a5a71198eba31e2e2b597833f699b28"
+dependencies = [
+ "critical-section",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -20,7 +29,7 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5deb64efa5bd81e31fcd1938615a6d98c82eafcbcd787162b6f63b91d6bac5b3"
 dependencies = [
- "rustc_version",
+ "rustc_version 0.2.3",
 ]
 
 [[package]]
@@ -35,6 +44,12 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "byteorder"
+version = "1.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
 [[package]]
 name = "chrono"
 version = "0.4.23"
@@ -186,6 +201,7 @@ dependencies = [
  "embedded-hal 0.2.7",
  "embedded-hal 1.0.0-alpha.9",
  "fugit",
+ "heapless",
  "itertools",
  "nb 1.0.0",
  "panic-halt",
@@ -194,7 +210,7 @@ dependencies = [
  "rand_core",
  "rp2040-boot2",
  "rp2040-hal",
- "rp2040-hal-macros",
+ "rp2040-hal-macros 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rp2040-pac",
  "rtic-monotonic",
  "usb-device",
@@ -202,6 +218,28 @@ dependencies = [
  "void",
 ]
 
+[[package]]
+name = "hash32"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0c35f58762feb77d74ebe43bdbc3210f09be9fe6742234d573bacc26ed92b67"
+dependencies = [
+ "byteorder",
+]
+
+[[package]]
+name = "heapless"
+version = "0.7.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db04bc24a18b9ea980628ecf00e6c0264f3c1426dac36c00cb49b6fbad8b0743"
+dependencies = [
+ "atomic-polyfill",
+ "hash32",
+ "rustc_version 0.4.0",
+ "spin",
+ "stable_deref_trait",
+]
+
 [[package]]
 name = "itertools"
 version = "0.10.5"
@@ -211,6 +249,16 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "lock_api"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "435011366fe56583b16cf956f9df0095b405b82d76425bc8981c0e22e60ec4df"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
 [[package]]
 name = "nb"
 version = "0.1.3"
@@ -348,11 +396,10 @@ dependencies = [
 [[package]]
 name = "rp2040-hal"
 version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ecf1b975581f0cac465247c464e7d2b8d93c7a5fceb4eb13b7b8517f4f85f6d"
 dependencies = [
  "cortex-m",
  "critical-section",
+ "embedded-dma",
  "embedded-hal 0.2.7",
  "fugit",
  "itertools",
@@ -360,13 +407,22 @@ dependencies = [
  "paste",
  "pio",
  "rand_core",
- "rp2040-hal-macros",
+ "rp2040-hal-macros 0.1.0",
  "rp2040-pac",
  "usb-device",
  "vcell",
  "void",
 ]
 
+[[package]]
+name = "rp2040-hal-macros"
+version = "0.1.0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "rp2040-hal-macros"
 version = "0.1.0"
@@ -402,9 +458,24 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 dependencies = [
- "semver",
+ "semver 0.9.0",
 ]
 
+[[package]]
+name = "rustc_version"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa0f585226d2e68097d4f95d113b15b83a82e819ab25717ec0590d9584ef366"
+dependencies = [
+ "semver 1.0.16",
+]
+
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
 [[package]]
 name = "semver"
 version = "0.9.0"
@@ -414,12 +485,27 @@ dependencies = [
  "semver-parser",
 ]
 
+[[package]]
+name = "semver"
+version = "1.0.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "58bc9567378fc7690d6b2addae4e60ac2eeea07becb2c64b9f218b53865cba2a"
+
 [[package]]
 name = "semver-parser"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
+[[package]]
+name = "spin"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f6002a767bff9e83f8eeecf883ecb8011875a21ae8da43bffb817a57e78cc09"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.0"

Cargo.toml

@@ -21,13 +21,14 @@ nb = "1.0"
 rp2040-pac = "0.4.0"
 paste = "1.0"
 pio = "0.2.0"
-rp2040-hal = "0.7.0"
+rp2040-hal = { path = "../rp-hal/rp2040-hal/" }
 rp2040-hal-macros = "0.1.0"
 usb-device = "0.2.9"
 vcell = "0.1"
 void = { version = "1.0.2", default-features = false }
 rand_core = "0.6.3"
 critical-section = { version = "1.0.0" }
+heapless = "0.7.16"
 
 chrono = { version = "0.4", default-features = false, optional = true }
 

src/main.rs

@@ -10,6 +10,7 @@
 #![no_std]
 #![no_main]
 
+use embedded_hal::digital::v2::OutputPin;
 // Ensure we halt the program on panic (if we don't mention this crate it won't
 // be linked)
 use panic_halt as _;
@@ -18,6 +19,7 @@ use panic_halt as _;
 use rp2040_hal as hal;
 
 // Some traits we need
+use cortex_m::singleton;
 use embedded_hal::PwmPin;
 use fugit::RateExtU32;
 use rp2040_hal::clocks::Clock;
@@ -26,9 +28,14 @@ use rp2040_hal::clocks::Clock;
 // register access
 use hal::pac;
 
+// SPI + DMA
+use hal::dma::{bidirectional, DMAExt};
+
 // UART related types
 use hal::uart::{DataBits, StopBits, UartConfig};
 
+use heapless::String;
+
 /// The linker will place this boot block at the start of our program image. We
 /// need this to help the ROM bootloader get our code up and running.
 /// Note: This boot block is not necessary when using a rp-hal based BSP
@@ -141,6 +148,50 @@ fn main() -> ! {
 
     uart.write_full_blocking(b"Initialization complete!\r\n");
 
+    // SPI CS pin is controlled by software
+    let mut spi_cs = pins.gpio5.into_push_pull_output();
+    spi_cs.set_high().unwrap();
+
+    // These are implicitly used by the spi driver if they are in the correct mode
+    let _spi_sclk = pins.gpio2.into_mode::<hal::gpio::FunctionSpi>();
+    let _spi_mosi = pins.gpio3.into_mode::<hal::gpio::FunctionSpi>();
+    let _spi_miso = pins.gpio4.into_mode::<hal::gpio::FunctionSpi>();
+    let spi = hal::spi::Spi::<_, _, 8>::new(pac.SPI0);
+
+    // Exchange the uninitialised SPI driver for an initialised one
+    let spi = spi.init(
+        &mut pac.RESETS,
+        clocks.peripheral_clock.freq(),
+        1_000_000u32.Hz(),
+        &embedded_hal::spi::MODE_0,
+    );
+
+    // Initialize DMA.
+    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();
+
+    // 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 data: String<16> = String::from(adc_value);
+
+        uart.write_full_blocking(b"Read ADC value: ");
+        uart.write_full_blocking(data.as_bytes());
+        uart.write_full_blocking(b"\r\n");
+    }
+
     // Infinite loop, fading LED up and down
     loop {
         for i in 0..ch_val.len() {