From e8fd09ba5b93fcd5859bb76ab0c95fc0fdf26573 Mon Sep 17 00:00:00 2001
From: Benjamin Koch <bbbsnowball@gmail.com>
Date: Fri, 9 Jun 2023 18:24:29 +0200
Subject: [PATCH] make baud rate configurable
---
firmware/rust1/src/rs485.rs | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/firmware/rust1/src/rs485.rs b/firmware/rust1/src/rs485.rs
index 93165c6..4df0d0d 100644
--- a/firmware/rust1/src/rs485.rs
+++ b/firmware/rust1/src/rs485.rs
@@ -3,6 +3,7 @@ use embassy_futures::select::*;
use embassy_rp::gpio;
use embassy_rp::pac;
use embassy_rp::interrupt::UART0_IRQ;
+use embassy_rp::uart::Parity;
use embassy_time::{Duration, Timer};
use embassy_embedded_hal::SetConfig;
use embassy_rp::peripherals::{self, UART0};
@@ -12,6 +13,8 @@ use embassy_rp::relocate::RelocatedProgram;
use embassy_rp::Peripheral;
use {defmt_rtt as _, panic_probe as _};
use fixed::traits::ToFixed;
+use fixed::types::U24F8;
+use fixed::types::U56F8;
use fixed_macro::types::U56F8;
use futures::Future;
@@ -37,6 +40,8 @@ pub struct RS485<H: RS485Handler> {
dma_channel: peripherals::DMA_CH0,
tx_dma_channel: peripherals::DMA_CH2,
rx: UartRx<'static, UART0, uart::Async>,
+ uart_baud_rate: u32,
+ uart_parity: Parity,
handler: H
}
@@ -90,7 +95,13 @@ impl<H: RS485Handler> RS485<H> {
rx_dma_channel,
uart_config,
);
- RS485 { pio, rx_pin: rx_pin_for_autobaud, tx_pin, tx_en_pin, dma_channel, tx_dma_channel, rx: uart_rx, handler }
+ RS485 {
+ pio, rx_pin: rx_pin_for_autobaud, tx_pin, tx_en_pin, dma_channel, tx_dma_channel,
+ rx: uart_rx,
+ uart_baud_rate: uart_config.baudrate,
+ uart_parity: uart_config.parity,
+ handler,
+ }
}
pub async fn run_task(mut self: Self) {
@@ -208,8 +219,9 @@ impl<H: RS485Handler> RS485<H> {
let mut cfg = Config::default();
let loaded_program = common.load_program(&relocated);
cfg.use_program(&loaded_program, &[]);
+ const CPU_CLK: u32 = 125_000_000;
const SM_FREQ: u32 = 25_000_000;
- cfg.clock_divider = (U56F8!(125_000_000) / U56F8!(25_000_000 /* SM_FREQ */)).to_fixed();
+ cfg.clock_divider = U24F8::from_num(CPU_CLK / SM_FREQ);
cfg.shift_in = ShiftConfig {
auto_fill: true,
threshold: 32,
@@ -230,7 +242,10 @@ impl<H: RS485Handler> RS485<H> {
// Timeout: Modbus wants 3.5 char times between frames but we should detect the end of a frame
// after 1.5 char times. This is 0.86 ms at 19200 baud (8e1, i.e. 11 baud times per char).
// We need two clocks for each loop.
- let timeout_start_value = (SM_FREQ as f32 * 0.86e-3 / 2.) as u32;
+ //let timeout_start_value = (SM_FREQ as f32 * 0.86e-3 / 2.) as u32;
+ let symbols_per_byte = if self.uart_parity == Parity::ParityNone { 10 } else { 11 };
+ let timeout_seconds = 1.5 * symbols_per_byte as f32 * 1000. / self.uart_baud_rate as f32;
+ let timeout_start_value = (SM_FREQ as f32 * timeout_seconds / 2.) as u32;
sm.tx().push(timeout_start_value);
info!("timeout_start_value: {} = 0x{:08x}", timeout_start_value, timeout_start_value);
@@ -264,8 +279,7 @@ impl<H: RS485Handler> RS485<H> {
let tx_en_pin_pio = common.make_pio_pin(self.tx_en_pin);
let loaded_program = common.load_program(&relocated);
cfg.use_program(&loaded_program, &[&tx_en_pin_pio, &tx_pin_pio]);
- const BAUD_RATE: u32 = 19200;
- cfg.clock_divider = (U56F8!(125_000_000) / U56F8!(76800 /* BAUD_RATE*4 */)).to_fixed();
+ cfg.clock_divider = (U56F8::from_num(CPU_CLK) / U56F8::from_num(self.uart_baud_rate*4)).to_fixed();
cfg.shift_out = ShiftConfig {
auto_fill: false,
threshold: 32,
--
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