From 94305a758a2e626ab6f1c37183d1a715351b8d33 Mon Sep 17 00:00:00 2001
From: James P <no@no.com>
Date: Fri, 10 Nov 2023 17:09:59 +0000
Subject: [PATCH] added ability to just set or unset break condition without
 specifying a time limit

---
 serial.go         |  3 +++
 serial_unix.go    | 17 +++++++++++++++++
 serial_windows.go | 18 ++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/serial.go b/serial.go
index abfd7f9..39a9e01 100644
--- a/serial.go
+++ b/serial.go
@@ -54,6 +54,9 @@ type Port interface {
 
 	// Break sends a break for a determined time
 	Break(time.Duration) error
+
+	// Set or unset break condition, allows timing to be done more precisely outside of this module
+	SetBreak(bool) error
 }
 
 // NoTimeout should be used as a parameter to SetReadTimeout to disable timeout.
diff --git a/serial_unix.go b/serial_unix.go
index f6ec896..ba5a4fe 100644
--- a/serial_unix.go
+++ b/serial_unix.go
@@ -118,12 +118,14 @@ func (port *unixPort) Write(p []byte) (n int, err error) {
 }
 
 func (port *unixPort) Break(t time.Duration) error {
+	// set break
 	if err := unix.IoctlSetInt(port.handle, ioctlTiocsbrk, 0); err != nil {
 		return err
 	}
 
 	time.Sleep(t)
 
+	// clear break
 	if err := unix.IoctlSetInt(port.handle, ioctlTioccbrk, 0); err != nil {
 		return err
 	}
@@ -131,6 +133,21 @@ func (port *unixPort) Break(t time.Duration) error {
 	return nil
 }
 
+func (port *unixPort) SetBreak(setBreak bool) error {
+	if setBreak {
+		// set break
+		if err := unix.IoctlSetInt(port.handle, ioctlTiocsbrk, 0); err != nil {
+			return err
+		}
+	} else {
+		// clear break
+		if err := unix.IoctlSetInt(port.handle, ioctlTioccbrk, 0); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (port *unixPort) SetMode(mode *Mode) error {
 	settings, err := port.getTermSettings()
 	if err != nil {
diff --git a/serial_windows.go b/serial_windows.go
index 287856a..70dbaf0 100644
--- a/serial_windows.go
+++ b/serial_windows.go
@@ -386,12 +386,14 @@ func (port *windowsPort) SetReadTimeout(timeout time.Duration) error {
 }
 
 func (port *windowsPort) Break(d time.Duration) error {
+	// set break
 	if err := setCommBreak(port.handle); err != nil {
 		return &PortError{causedBy: err}
 	}
 
 	time.Sleep(d)
 
+	// unset break
 	if err := clearCommBreak(port.handle); err != nil {
 		return &PortError{causedBy: err}
 	}
@@ -399,6 +401,22 @@ func (port *windowsPort) Break(d time.Duration) error {
 	return nil
 }
 
+func (port *windowsPort) SetBreak(setBreak bool) error {
+	if setBreak {
+		// set break
+		if err := setCommBreak(port.handle); err != nil {
+			return &PortError{causedBy: err}
+		}
+	} else {
+		// unset break
+		if err := clearCommBreak(port.handle); err != nil {
+			return &PortError{causedBy: err}
+		}
+	}
+
+	return nil
+}
+
 func createOverlappedEvent() (*syscall.Overlapped, error) {
 	h, err := createEvent(nil, true, false, nil)
 	return &syscall.Overlapped{HEvent: h}, err