rust: Add uart-passthrough

README.md

@@ -125,6 +125,13 @@ The amount of pressure applied determines the radius of the state change.
 
 [README](rust/game-of-life/README.md)
 
+rust/uart-passthrough
+---------------------
+
+Pass through UART from host to the ESP8285 WIFI chip.
+
+[README](rust/uart-passthrough/README.md)
+
 ROM re'ing
 ===========
 

rust/Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "mandelbrot",
     "game-of-life",
     "accelerometer",
+    "uart-passthrough",
 ]
 
 [patch.crates-io]

rust/uart-passthrough/.cargo/config

@@ -0,0 +1,8 @@
+[target.riscv64gc-unknown-none-elf]
+rustflags = [
+  "-C", "link-arg=-Tmemory.x",
+  "-C", "link-arg=-Tlink.x",
+]
+
+[build]
+target = "riscv64gc-unknown-none-elf"

rust/uart-passthrough/.gitignore

@@ -0,0 +1,2 @@
+/target
+**/*.rs.bk

rust/uart-passthrough/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "uart-passthrough"
+version = "0.1.0"
+authors = ["W.J. van der Laan <laanwj@protonmail.com>"]
+edition = "2018"
+
+[dependencies]
+nb = "0.1.1"
+riscv-rt = "0.5.0"
+k210-hal = "0.1.0"
+riscv = "0.5"
+k210-shared = { path = "../k210-shared" }

rust/uart-passthrough/README.md

@@ -0,0 +1,6 @@
+# `uart-passthrough`
+
+Pass through UART from host to the ESP8285 WIFI chip.
+
+Any input from the host is forwarded to the ESP8285, and any input from the ESP8285
+is forwarded to the host. Currently only supports a fixed baudrate of 115200.

rust/uart-passthrough/src/main.rs

@@ -0,0 +1,41 @@
+#![allow(dead_code)]
+#![allow(non_snake_case)]
+#![allow(non_camel_case_types)]
+#![no_std]
+#![no_main]
+
+use k210_hal::pac;
+use k210_hal::prelude::*;
+use k210_shared::board::def::io;
+use k210_shared::soc::fpioa;
+use k210_shared::soc::sysctl;
+use nb::block;
+use riscv_rt::entry;
+
+#[entry]
+fn main() -> ! {
+    let p = pac::Peripherals::take().unwrap();
+    let clocks = k210_hal::clock::Clocks::new();
+
+    // Configure UARTHS (→host)
+    let serial = p.UARTHS.constrain(115_200.bps(), &clocks);
+    let (mut tx, mut rx) = serial.split();
+
+    // Configure UART1 (→WIFI)
+    sysctl::clock_enable(sysctl::clock::UART1);
+    sysctl::reset(sysctl::reset::UART1);
+    fpioa::set_function(io::WIFI_RX as u8, fpioa::function::UART1_TX);
+    fpioa::set_function(io::WIFI_TX as u8, fpioa::function::UART1_RX);
+    let wifi_serial = p.UART1.constrain(115_200.bps(), &clocks);
+    let (mut wtx, mut wrx) = wifi_serial.split();
+
+    // Relay characters between UARTs
+    loop {
+        if let Ok(ch) = wrx.read() {
+            let _res = block!(tx.write(ch));
+        }
+        if let Ok(ch) = rx.read() {
+            let _res = block!(wtx.write(ch));
+        }
+    }
+}