From 43ec8916b49023558db7fb286519f34130af85a5 Mon Sep 17 00:00:00 2001
From: Claas <claas@claas.dev>
Date: Mon, 4 Nov 2024 22:26:15 +0100
Subject: [PATCH] Try out buffered UART to allow variable length for modbus
 responses

this is useful because temperature sensor response has different length than the set set point response
---
 fan-controller/src/fan.rs  | 16 +++++++++++-----
 fan-controller/src/main.rs | 25 +++++++++++++++++++++----
 2 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/fan-controller/src/fan.rs b/fan-controller/src/fan.rs
index a4f4704..949cc11 100644
--- a/fan-controller/src/fan.rs
+++ b/fan-controller/src/fan.rs
@@ -7,9 +7,13 @@ use defmt::{error, info, Format};
 use embassy_rp::dma::Channel;
 use embassy_rp::gpio::{Level, Output, Pin};
 use embassy_rp::interrupt::typelevel::Binding;
-use embassy_rp::uart::{Async, DataBits, InterruptHandler, Parity, RxPin, StopBits, TxPin, Uart};
+use embassy_rp::uart::{
+    Async, BufferedInterruptHandler, BufferedUart, DataBits, InterruptHandler, Parity, RxPin,
+    StopBits, TxPin, Uart,
+};
 use embassy_rp::{uart, Peripheral};
 use embassy_time::{block_for, with_timeout, Duration, TimeoutError, Timer};
+use embedded_io_async::{Read, Write};
 
 pub(crate) const BAUD_RATE: u32 = 19_200;
 pub(crate) fn get_configuration() -> uart::Config {
@@ -79,7 +83,7 @@ pub(crate) enum Fan {
 /// Modbus messages are sent through UART to MAX845 to control fans.
 /// The pin is used to enable the DE pin to switch between reading and writing
 pub(crate) struct Client<'a, UART: uart::Instance, PIN: Pin> {
-    uart: Uart<'a, UART, Async>,
+    uart: BufferedUart<'a, UART>,
     driver_enable: Output<'a, PIN>,
 }
 
@@ -88,12 +92,14 @@ impl<'a, UART: uart::Instance, PIN: Pin> Client<'a, UART, PIN> {
         uart: impl Peripheral<P = UART> + 'a,
         tx: impl Peripheral<P = impl TxPin<UART>> + 'a,
         rx: impl Peripheral<P = impl RxPin<UART>> + 'a,
-        irq: impl Binding<UART::Interrupt, InterruptHandler<UART>>,
+        irq: impl Binding<UART::Interrupt, BufferedInterruptHandler<UART>>,
         tx_dma: impl Peripheral<P = impl Channel> + 'a,
         rx_dma: impl Peripheral<P = impl Channel> + 'a,
         driver_enable: impl Peripheral<P = PIN> + 'a,
+        tx_buffer: &'a mut [u8],
+        rx_buffer: &'a mut [u8],
     ) -> Self {
-        let uart = Uart::new(uart, tx, rx, irq, tx_dma, rx_dma, get_configuration());
+        let uart = BufferedUart::new(uart, irq, tx, rx, tx_buffer, rx_buffer, get_configuration());
         let driver_enable = Output::new(driver_enable, Level::Low);
 
         Self {
@@ -110,7 +116,7 @@ impl<'a, UART: uart::Instance, PIN: Pin> Client<'a, UART, PIN> {
         // As ref because &[u8; 8] is not the same as &[u8]
         let result = with_timeout(
             configuration::FAN_TIMEOUT,
-            self.uart.write(message.as_ref()),
+            self.uart.write_all(message.as_ref()),
         )
         .await?;
         // let result = self.uart.blocking_write(message.as_ref());
diff --git a/fan-controller/src/main.rs b/fan-controller/src/main.rs
index 9b6aefd..0dca458 100644
--- a/fan-controller/src/main.rs
+++ b/fan-controller/src/main.rs
@@ -28,7 +28,7 @@ use embassy_rp::peripherals::{
     DMA_CH0, PIN_12, PIN_13, PIN_18, PIN_23, PIN_24, PIN_25, PIN_29, PIN_4, PIO0, UART0,
 };
 use embassy_rp::pio::{InterruptHandler as PioInterruptHandler, Pio, PioPin};
-use embassy_rp::uart::{InterruptHandler as UartInterruptHandler, Uart};
+use embassy_rp::uart::{BufferedInterruptHandler, InterruptHandler as UartInterruptHandler, Uart};
 use embassy_rp::{bind_interrupts, dma, pio, uart, Peripheral, Peripherals};
 use embassy_sync::blocking_mutex::raw::{CriticalSectionRawMutex, NoopRawMutex};
 use embassy_sync::channel;
@@ -74,7 +74,7 @@ mod mqtt;
 
 bind_interrupts!(struct Irqs {
     PIO0_IRQ_0 => PioInterruptHandler<PIO0>;
-    UART0_IRQ  => UartInterruptHandler<UART0>;
+    UART0_IRQ  => BufferedInterruptHandler<UART0>;
 });
 
 #[embassy_executor::task]
@@ -1013,7 +1013,15 @@ async fn mqtt_task(
     }
 
     //TODO cancel all tasks when client loses connection
-    join5(listen, talk, keep_alive, set_up, update_homeassistant()).await;
+    join5(
+        listen,
+        talk,
+        keep_alive,
+        set_up,
+        // Join because there is only a join with max 5 arguments 😬
+        join(update_homeassistant(), poll_sensors()),
+    )
+    .await;
 }
 
 /// This task handles inputs from physical buttons to change the fan speed
@@ -1166,7 +1174,16 @@ async fn main(spawner: Spawner) {
 
     // UART
 
-    let client = fan::Client::new(uart0, pin_12, pin_13, Irqs, dma_ch1, dma_ch2, pin_4);
+    /// Transmit buffer for UART
+    static TX_BUFFER: StaticCell<[u8; 16]> = StaticCell::new();
+    let tx_buffer = &mut TX_BUFFER.init([0; 16])[..];
+    /// Receive buffer for UART
+    static RX_BUFFER: StaticCell<[u8; 16]> = StaticCell::new();
+    let rx_buffer = &mut RX_BUFFER.init([0; 16])[..];
+
+    let client = fan::Client::new(
+        uart0, pin_12, pin_13, Irqs, dma_ch1, dma_ch2, pin_4, tx_buffer, rx_buffer,
+    );
     //TODO load fan setting from fan
     // Inner scope to drop the guard after assigning
     {
-- 
2.51.2