Added '-padding' option to uartdmx plugin.

plugins/uartdmx/README.md

@@ -0,0 +1,34 @@
+Native UART DMX Plugin
+======================
+
+This plugin drives a supported POSIX UART (plus extensions) to produce a
+direct DMX output stream. The host needs to create the DMX stream itself as
+there is no external microcontroller.
+
+This is tested with the on-board UART of the Raspberry Pi. See here for a
+possible schematic:
+http://eastertrail.blogspot.co.uk/2014/04/command-and-control-ii.html
+
+
+## Config file: `ola-uartdmx.conf`
+
+`enabled = true`
+Enable this plugin (DISABLED by default).
+
+`device = /dev/ttyAMA0`
+The device to use for DMX output (optional). Multiple devices are supported
+if the hardware exists. On later software it may also be /dev/serial0.
+Using USB-serial adapters is not supported (try the
+*ftdidmx* plugin instead).
+
+
+### Per Device Settings (using above device name)
+
+`<device>-break = 100`
+The DMX break time in microseconds for this device (optional).
+
+`<device>-malf = 100`
+The Mark After Last Frame time in microseconds for this device (optional).
+
+`<device>-padding = 0` Minimal slots count in DMX frame (optional). 
+Default is 0, which allows empty frame. Using minimal timing, frame period reaches 140 microseconds, while standard requires minimum 1204us. Using BREAK=88us and MAB=8us, frame has to include 25 slots, that gives frame period 1240us. 

plugins/uartdmx/UartDmxDevice.cpp

@@ -34,8 +34,10 @@ using std::string;
 
 const char UartDmxDevice::K_MALF[] = "-malf";
 const char UartDmxDevice::K_BREAK[] = "-break";
+const char UartDmxDevice::K_PADDING[] = "-padding";
 const unsigned int UartDmxDevice::DEFAULT_BREAK = 100;
 const unsigned int UartDmxDevice::DEFAULT_MALF = 100;
+const unsigned int UartDmxDevice::DEFAULT_PADDING = 0;
 
 
 UartDmxDevice::UartDmxDevice(AbstractPlugin *owner,
@@ -57,7 +59,10 @@ UartDmxDevice::UartDmxDevice(AbstractPlugin *owner,
   if (!StringToInt(m_preferences->GetValue(DeviceMalfKey()), &m_malft)) {
     m_malft = DEFAULT_MALF;
   }
-  m_widget.reset(new UartWidget(path));
+  if (!StringToInt(m_preferences->GetValue(DevicePaddingKey()), &m_paddingt)) {
+    m_paddingt = DEFAULT_PADDING;
+  }
+  m_widget.reset(new UartWidget(path, m_paddingt));
 }
 
 UartDmxDevice::~UartDmxDevice() {
@@ -77,6 +82,9 @@ string UartDmxDevice::DeviceMalfKey() const {
 string UartDmxDevice::DeviceBreakKey() const {
   return m_path + K_BREAK;
 }
+string UartDmxDevice::DevicePaddingKey() const {
+  return m_path + K_PADDING;
+}
 
 /**
  * Set the default preferences for this one Device
@@ -94,6 +102,9 @@ void UartDmxDevice::SetDefaults() {
   save |= m_preferences->SetDefaultValue(DeviceMalfKey(),
                                          UIntValidator(8, 1000000),
                                          DEFAULT_MALF);
+  save |= m_preferences->SetDefaultValue(DevicePaddingKey(),
+                                         UIntValidator(0, 512),
+                                         DEFAULT_PADDING);
   if (save) {
     m_preferences->Save();
   }

plugins/uartdmx/UartDmxDevice.h

@@ -52,6 +52,7 @@ class UartDmxDevice : public Device {
   // Per device options
   std::string DeviceBreakKey() const;
   std::string DeviceMalfKey() const;
+  std::string DevicePaddingKey() const;
   void SetDefaults();
 
   std::auto_ptr<UartWidget> m_widget;
@@ -60,11 +61,14 @@ class UartDmxDevice : public Device {
   const std::string m_path;
   unsigned int m_breakt;
   unsigned int m_malft;
+  unsigned int m_paddingt;
 
   static const unsigned int DEFAULT_MALF;
   static const char K_MALF[];
   static const unsigned int DEFAULT_BREAK;
   static const char K_BREAK[];
+  static const unsigned int DEFAULT_PADDING;
+  static const char K_PADDING[];
 
   DISALLOW_COPY_AND_ASSIGN(UartDmxDevice);
 };

plugins/uartdmx/UartWidget.cpp

@@ -46,6 +46,7 @@
 #include "ola/io/IOUtils.h"
 #include "ola/Logging.h"
 #include "plugins/uartdmx/UartWidget.h"
+#include "plugins/uartdmx/UartDmxDevice.h"
 
 namespace ola {
 namespace plugin {
@@ -54,8 +55,9 @@ namespace uartdmx {
 using std::string;
 using std::vector;
 
-UartWidget::UartWidget(const string& path)
+UartWidget::UartWidget(const std::string &path, unsigned int padding)
     : m_path(path),
+      m_padding(padding),
       m_fd(NOT_OPEN) {
 }
 
@@ -122,6 +124,10 @@ bool UartWidget::Write(const ola::DmxBuffer& data) {
   buffer[0] = DMX512_START_CODE;
 
   data.Get(buffer + 1, &length);
+  if (length < m_padding) {
+      memset((buffer + 1 + length), 0x00, (m_padding - length) );
+      length = m_padding;
+    }
 
   if (write(m_fd, buffer, length + 1) <= 0) {
     // TODO(richardash1981): handle errors better as per the test code,

plugins/uartdmx/UartWidget.h

@@ -48,9 +48,9 @@ class UartWidget {
     /**
      * Construct a new UartWidget instance for one widget.
      * @param path The device file path of the serial port
+     * @param padding Minimum DMX frame slots count, padded with NULLs
      */
-    explicit UartWidget(const std::string &path);
-
+    explicit UartWidget(const std::string &path, unsigned int padding);
     /** Destructor */
     virtual ~UartWidget();
 
@@ -81,6 +81,7 @@ class UartWidget {
 
  private:
   const std::string m_path;
+  unsigned int m_padding;
 
   /**
    * variable to hold the Unix file descriptor used to open and manipulate