esp-rs · SergioGasquez · Jun 13, 2025 · May 30, 2025 · May 30, 2025 · May 30, 2025
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -29,6 +29,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `--after` options now work with `espflash board-info`, `espflash read-flash` and `espflash checksum-md5` (#867)
 - Add support for serial port configuration files. (#777)
 - Add a `check-app-descriptor` bool option to `ImageArgs` and add the flag to `flash` commad(#872)
+- `Connection::into_serial` to get the underlying port from the connection (#882)
 
 ### Changed
 
@@ -49,6 +50,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Updated bootloaders with `release/v5.4` ones from IDF (#857)
 - Refactor image formatting to allow supporting more image formats in a backward compatible way (#877)
 - Avoid having ESP-IDF format assumptions in the codebase (#877)
+- `Flasher` now takes the `Connection` in new, instead of constructing the connection inside `Flasher::connect` (#882)
+- `detect_chip` has moved to the `Connection` struct (#882)
+- `Flasher::into_serial` has been replaced by `Flasher::into_connection` (#882)
 
 ### Fixed
 
@@ -61,6 +65,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed a case where esplash transformed the firmware elf in a way that made it unbootable (#831)
 - The app descriptor is now correctly placed in the front of the bianry (#835)
 - espflash now extracts the MMU page size from the app descriptor (#835)
+- `ResetBeforeOperation` & `ResetAfterOperation` are now public, to allow the creation of a `Connection` (#882)
 
 ### Removed
 

diff --git a/cargo-espflash/src/main.rs b/cargo-espflash/src/main.rs
@@ -397,7 +397,7 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
     }
 
     if args.flash_args.monitor {
-        let pid = flasher.usb_pid();
+        let pid = flasher.connection().usb_pid();
 
         // The 26MHz ESP32-C2's need to be treated as a special case.
         if chip == Chip::Esp32c2
@@ -410,7 +410,12 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
 
         monitor_args.elf = Some(build_ctx.artifact_path);
 
-        monitor(flasher.into_serial(), Some(&elf_data), pid, monitor_args)
+        monitor(
+            flasher.into_connection().into_serial(),
+            Some(&elf_data),
+            pid,
+            monitor_args,
+        )
     } else {
         Ok(())
     }

diff --git a/espflash/src/bin/espflash.rs b/espflash/src/bin/espflash.rs
@@ -309,7 +309,7 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
     }
 
     if args.flash_args.monitor {
-        let pid = flasher.usb_pid();
+        let pid = flasher.connection().usb_pid();
 
         // The 26MHz ESP32-C2's need to be treated as a special case.
         if chip == Chip::Esp32c2
@@ -322,7 +322,12 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
 
         monitor_args.elf = Some(args.image);
 
-        monitor(flasher.into_serial(), Some(&elf_data), pid, monitor_args)
+        monitor(
+            flasher.into_connection().into_serial(),
+            Some(&elf_data),
+            pid,
+            monitor_args,
+        )
     } else {
         Ok(())
     }

diff --git a/espflash/src/cli/mod.rs b/espflash/src/cli/mod.rs
@@ -34,7 +34,10 @@ use self::{
     monitor::{LogFormat, check_monitor_args, monitor},
 };
 use crate::{
-    connection::reset::{ResetAfterOperation, ResetBeforeOperation},
+    connection::{
+        Connection,
+        reset::{ResetAfterOperation, ResetBeforeOperation},
+    },
     error::{Error, MissingPartition, MissingPartitionTable},
     flasher::{
         FLASH_SECTOR_SIZE,
@@ -435,16 +438,21 @@ pub fn connect(
         _ => unreachable!(),
     };
 
-    Ok(Flasher::connect(
+    let connection = Connection::new(
         *Box::new(serial_port),
         port_info,
-        args.baud.or(config.project_config.baudrate),
+        args.after,
+        args.before,
+        args.baud
+            .or(config.project_config.baudrate)
+            .unwrap_or(115_200),
+    );
+    Ok(Flasher::connect(
+        connection,
         !args.no_stub,
         !no_verify,
         !no_skip,
         args.chip,
-        args.after,
-        args.before,
     )?)
 }
 
@@ -618,7 +626,7 @@ pub fn print_board_info(flasher: &mut Flasher) -> Result<()> {
 /// Open a serial monitor
 pub fn serial_monitor(args: MonitorArgs, config: &Config) -> Result<()> {
     let mut flasher = connect(&args.connect_args, config, true, true)?;
-    let pid = flasher.usb_pid();
+    let pid = flasher.connection().usb_pid();
 
     let elf = if let Some(elf_path) = args.monitor_args.elf.clone() {
         let path = fs::canonicalize(elf_path).into_diagnostic()?;
@@ -646,7 +654,12 @@ pub fn serial_monitor(args: MonitorArgs, config: &Config) -> Result<()> {
         monitor_args.monitor_baud = 74_880;
     }
 
-    monitor(flasher.into_serial(), elf.as_deref(), pid, monitor_args)
+    monitor(
+        flasher.into_connection().into_serial(),
+        elf.as_deref(),
+        pid,
+        monitor_args,
+    )
 }
 
 /// Convert the provided firmware image from ELF to binary
@@ -1111,18 +1124,20 @@ pub fn write_bin(args: WriteBinArgs, config: &Config) -> Result<()> {
     )?;
 
     if args.monitor {
-        let pid = flasher.usb_pid();
+        let pid = flasher.connection().usb_pid();
         let mut monitor_args = args.monitor_args;
-
         if chip == Chip::Esp32c2
             && target_xtal_freq == XtalFrequency::_26Mhz
             && monitor_args.monitor_baud == 115_200
         {
-            // 115_200 * 26 MHz / 40 MHz = 74_880
             monitor_args.monitor_baud = 74_880;
         }
-
-        monitor(flasher.into_serial(), None, pid, monitor_args)?;
+        monitor(
+            flasher.into_connection().into_serial(),
+            None,
+            pid,
+            monitor_args,
+        )?;
     }
 
     Ok(())

diff --git a/espflash/src/connection/mod.rs b/espflash/src/connection/mod.rs
@@ -35,6 +35,7 @@ use self::{
 };
 use crate::{
     error::{ConnectionError, Error, ResultExt, RomError, RomErrorKind},
+    flasher::stubs::CHIP_DETECT_MAGIC_REG_ADDR,
     targets::Chip,
 };
 
@@ -134,6 +135,7 @@ pub struct Connection {
     after_operation: ResetAfterOperation,
     before_operation: ResetBeforeOperation,
     pub(crate) secure_download_mode: bool,
+    pub(crate) baud: u32,
 }
 
 impl Connection {
@@ -143,6 +145,7 @@ impl Connection {
         port_info: UsbPortInfo,
         after_operation: ResetAfterOperation,
         before_operation: ResetBeforeOperation,
+        baud: u32,
     ) -> Self {
         Connection {
             serial,
@@ -151,6 +154,7 @@ impl Connection {
             after_operation,
             before_operation,
             secure_download_mode: false,
+            baud,
         }
     }
 
@@ -388,15 +392,15 @@ impl Connection {
     }
 
     /// Set baud rate for the serial port.
-    pub fn set_baud(&mut self, speed: u32) -> Result<(), Error> {
-        self.serial.set_baud_rate(speed)?;
-
+    pub fn set_baud(&mut self, baud: u32) -> Result<(), Error> {
+        self.serial.set_baud_rate(baud)?;
+        self.baud = baud;
         Ok(())
     }
 
     /// Get the current baud rate of the serial port.
-    pub fn baud(&self) -> Result<u32, Error> {
-        Ok(self.serial.baud_rate()?)
+    pub fn baud(&self) -> u32 {
+        self.baud
     }
 
     /// Run a command with a timeout defined by the command type.
@@ -618,6 +622,33 @@ impl Connection {
     pub(crate) fn is_using_usb_serial_jtag(&self) -> bool {
         self.port_info.pid == USB_SERIAL_JTAG_PID
     }
+
+    pub fn after_operation(&self) -> ResetAfterOperation {
+        self.after_operation
+    }
+    pub fn before_operation(&self) -> ResetBeforeOperation {
+        self.before_operation
+    }
+
+    /// Detect which chip is connected to this connection
+    pub fn detect_chip(
+        &mut self,
+        use_stub: bool,
+    ) -> Result<crate::targets::Chip, crate::error::Error> {
+        // Try to read the magic value from the chip
+        let magic = if use_stub {
+            self.with_timeout(CommandType::ReadReg.timeout(), |connection| {
+                connection.command(Command::ReadReg {
+                    address: CHIP_DETECT_MAGIC_REG_ADDR,
+                })
+            })?
+            .try_into()?
+        } else {
+            self.read_reg(CHIP_DETECT_MAGIC_REG_ADDR)?
+        };
+        debug!("Read chip magic value: 0x{:08x}", magic);
+        Chip::from_magic(magic)
+    }
 }
 
 mod encoder {