Fix the serial monitor when using 26MHz ESP32-C2

Author: jessebraham

cargo-espflash/src/main.rs

@@ -215,11 +215,25 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
 
     if args.flash_args.monitor {
         let pid = flasher.get_usb_pid()?;
+
+        let chip = flasher.chip();
+        let target = chip.into_target();
+
+        // The 26MHz ESP32-C2's need to be treated as a special case.
+        let default_baud = if chip == Chip::Esp32c2
+            && !args.connect_args.use_stub
+            && target.crystal_freq(&mut flasher.connection())? == 26
+        {
+            74_880
+        } else {
+            115_200
+        };
+
         monitor(
             flasher.into_interface(),
             Some(&elf_data),
             pid,
-            args.flash_args.monitor_baud.unwrap_or(115_200),
+            args.flash_args.monitor_baud.unwrap_or(default_baud),
         )
         .into_diagnostic()?;
     }

espflash/src/bin/espflash.rs

@@ -15,6 +15,7 @@ use espflash::{
     },
     image_format::ImageFormatKind,
     logging::initialize_logger,
+    targets::Chip,
     update::check_for_update,
 };
 use log::{debug, LevelFilter};
@@ -154,11 +155,24 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
     if args.flash_args.monitor {
         let pid = flasher.get_usb_pid()?;
 
+        let chip = flasher.chip();
+        let target = chip.into_target();
+
+        // The 26MHz ESP32-C2's need to be treated as a special case.
+        let default_baud = if chip == Chip::Esp32c2
+            && !args.connect_args.use_stub
+            && target.crystal_freq(&mut flasher.connection())? == 26
+        {
+            74_880
+        } else {
+            115_200
+        };
+
         monitor(
             flasher.into_interface(),
             Some(&elf_data),
             pid,
-            args.flash_args.monitor_baud.unwrap_or(115_200),
+            args.flash_args.monitor_baud.unwrap_or(default_baud),
         )
         .into_diagnostic()?;
     }

espflash/src/cli/mod.rs

@@ -285,7 +285,7 @@ pub fn board_info(args: ConnectArgs, config: &Config) -> Result<()> {
 
 /// Open a serial monitor
 pub fn serial_monitor(args: MonitorArgs, config: &Config) -> Result<()> {
-    let flasher = connect(&args.connect_args, config)?;
+    let mut flasher = connect(&args.connect_args, config)?;
     let pid = flasher.get_usb_pid()?;
 
     let elf = if let Some(elf_path) = args.elf {
@@ -297,11 +297,24 @@ pub fn serial_monitor(args: MonitorArgs, config: &Config) -> Result<()> {
         None
     };
 
+    let chip = flasher.chip();
+    let target = chip.into_target();
+
+    // The 26MHz ESP32-C2's need to be treated as a special case.
+    let default_baud = if chip == Chip::Esp32c2
+        && !args.connect_args.use_stub
+        && target.crystal_freq(&mut flasher.connection())? == 26
+    {
+        74_880
+    } else {
+        115_200
+    };
+
     monitor(
         flasher.into_interface(),
         elf.as_deref(),
         pid,
-        args.connect_args.baud.unwrap_or(115_200),
+        args.connect_args.baud.unwrap_or(default_baud),
     )
     .into_diagnostic()?;