Add functionality for automatically identifying available COM ports.

flash.ps1

@@ -2,9 +2,90 @@ param(
   [String]$COMPort,
   [switch]$Extras,
   [switch]$ResetAfterFlash,
+  [switch]$WriteMicropython,
+  [ValidateSet("ESP32","ESP8266","ESP8285","PYBv1.0","PYBv1.1","PYBLite","PYBv3")]
+    [string]$BoardType,
   [switch]$Verbose,
   [String[]]$Libs
 )
+<#
+Supported board types (at time of writing) for MicroPython are:
+- esp32, esp8266 (and esp8285 by extension)
+- stm32, teensy
+- CC3200
+Boards themselves:
+STM32-
+- pyBoard (v1.0, v1.1, Lite, v3) and chinese clones of pyBoard (uses v3 layout)
+- Espruino Pico
+- Olimex STM32 405STK, E407, H405, H407, P407
+- ST Micro Discovery STM32F401, F407, F429, F746
+- Teensy 3.1, 3.5, 3.6
+Not going to list supported Espressif ESP8266, ESP8285 and ESP32 boards because the list is endless.
+#>
+
+#TODO Get-MicroPythonFirmware {}
+######## Download latest firmware from website or whatever
+#TODO Write-MicroPythonFirmware {}
+######## esptool(.py)? erase_flash, then write_flash - erase_flash only needed if it's a fresh install
+#TODO Update-uPyConfig {} - to dynamically generate a board config from PS values
+######## uPyConfig.py will contain template values and will become uPyConfig.tpl
+
+Function Find-SerialPort {
+    param (
+        [switch]$DeviceNameOnly,
+        [switch]$First
+    )
+    #On OSX, all serial devices are created with both a cu. and tty. file
+    # "cu" is "Call-Up", where we initiate the connection to the device
+    # "tty" is "Totally Terminal, Yeah", where the device initiates the connection
+    #On Linux, all serial devices have one device file. While simpler, this means
+    # more work is needed in order to determine what serial devices are present.
+    # Possible way of determining is to see if the owning group is 'dialout'?
+    #On Windows, all serial devices are registered with COM ports.
+
+    #On Windows, if running Windows PowerShell rather than pwsh, $IsWindows will be undefined
+    # but we can safely assume that $IsWindows being null categorically means we're on windows
+    # because Microsoft have never released Windows PowerShell on anything other than windows.
+    #Remember the distinction between Windows PowerShell and the open-source PowerShell (pwsh)
+    If ($IsWindows -or $IsWindows -eq $Null) {
+        $Devices=change.exe port /query | ? { $_ -notlike '*DosDevices*' }
+        $Devices=($Devices|%{$device=$_ -split ' = ';[PSCustomObject]@{
+            Name = $device[0]
+            File = $device[1]
+        }})
+    } ElseIf ($IsMacOS) {
+        $Devices=Get-ChildItem -Path /dev -Filter 'cu.*' | ? { $_.Name -notlike '*Bluetooth*' }
+        $Devices=@($Devices|%{[PSCustomObject]@{
+            Name = $_.Name
+            File = ($_|Convert-Path)
+        }})
+    } ElseIf ($IsLinux) {
+        $Devices=Get-ChildItem -Path /dev -File | ? { (stat -c '%G' ($_|Convert-Path)) -ieq 'dialout' }
+        $Devices=@($Devices|%{[PSCustomObject]@{
+            Name = $_.Name
+            File = ($_|Convert-Path)
+        }})
+    } Else {
+        #Sorry FreeBSD
+        Write-Error -Message "OS currently unsupported for this function" -ErrorAction Stop
+    }
+    If ($Devices.Count -eq 0) {
+        Write-Error -Message "No serial ports found on system" -ErrorAction Stop
+    }
+    If ($First) {
+        If ($DeviceNameOnly) {
+            $Devices[0].Name
+        } Else {
+            $Devices[0]
+        }
+    } Else {
+        If ($DeviceNameOnly) {
+            $Devices | % { $_.Name }
+        } Else {
+            $Devices
+        }
+    }
+}
 
 Function Find-LibraryFile {
   [cmdletbinding()]