Squashed/Edited commit of the following:

commit ba336aa
Author: Bill C <[email protected]>
Date:   Wed Mar 5 20:36:21 2025 -0600

    Add 30s retry to USBRelay Init for reliable boot-time USB detection

    Add 30s retry to USBRelay Init for reliable boot-time USB detection
    - Added delay to handle USB enumeration timing (~15-30s)
    - Ensures CH340 and ICStation relays initialize consistently

commit 39902f9
Author: Bill C <[email protected]>
Date:   Sun Mar 2 20:46:19 2025 -0600

    Revert "trying stuff until I get it"

    This reverts commit c6bd365.

commit c6bd365
Author: Bill C <[email protected]>
Date:   Sun Mar 2 08:44:18 2025 -0600

    trying stuff until I get it

commit 0c0d46a
Author: Bill Carriveau <[email protected]>
Date:   Sat Mar 1 09:27:26 2025 -0600

    Update co-other.php

    Trying to keep things the way they were before. :)

commit f53ad80
Author: Bill C <[email protected]>
Date:   Fri Feb 28 23:16:46 2025 -0600

    Add CH340 UsbRelay

    Have compiling and verified working on pi

Author: dkulp

src/channeloutput/USBRelay.cpp

@@ -17,15 +17,13 @@
 #include "../Warnings.h"
 #include "../log.h"
 
+#include "Plugin.h"
 #include "USBRelay.h"
-#include "serialutil.h"
 
-#include "Plugin.h"
 class USBRelayPlugin : public FPPPlugins::Plugin, public FPPPlugins::ChannelOutputPlugin {
 public:
     USBRelayPlugin() :
-        FPPPlugins::Plugin("USBRelay") {
-    }
+        FPPPlugins::Plugin("USBRelay") {}
     virtual ChannelOutput* createChannelOutput(unsigned int startChannel, unsigned int channelCount) override {
         return new USBRelayOutput(startChannel, channelCount);
     }
@@ -39,19 +37,12 @@ FPPPlugins::Plugin* createPlugin() {
 
 /////////////////////////////////////////////////////////////////////////////
 
-/*
- *
- */
-USBRelayOutput::USBRelayOutput(unsigned int startChannel,
-                               unsigned int channelCount) :
+USBRelayOutput::USBRelayOutput(unsigned int startChannel, unsigned int channelCount) :
     ChannelOutput(startChannel, channelCount), SerialChannelOutput(), m_subType(RELAY_DVC_UNKNOWN), m_relayCount(0) {
     LogDebug(VB_CHANNELOUT, "USBRelayOutput::USBRelayOutput(%u, %u)\n",
              startChannel, channelCount);
 }
 
-/*
- *
- */
 USBRelayOutput::~USBRelayOutput() {
     LogDebug(VB_CHANNELOUT, "USBRelayOutput::~USBRelayOutput()\n");
 }
@@ -60,9 +51,6 @@ void USBRelayOutput::GetRequiredChannelRanges(const std::function<void(int, int)
     addRange(m_startChannel, m_startChannel + m_relayCount - 1);
 }
 
-/*
- *
- */
 int USBRelayOutput::Init(Json::Value config) {
     LogDebug(VB_CHANNELOUT, "USBRelayOutput::Init(JSON)\n");
 
@@ -72,13 +60,16 @@ int USBRelayOutput::Init(Json::Value config) {
         m_subType = RELAY_DVC_BIT;
     else if (subType == "ICStation")
         m_subType = RELAY_DVC_ICSTATION;
+    else if (subType == "CH340")
+        m_subType = RELAY_DVC_CH340;
 
     m_relayCount = config["channelCount"].asInt();
 
     if (m_subType == RELAY_DVC_UNKNOWN) {
-        LogErr(VB_CHANNELOUT, "Invalid Config: invalid type\n");
+        LogErr(VB_CHANNELOUT, "Invalid Config, missing device or invalid type\n");
         return 0;
     }
+
     if (!setupSerialPort(config, 9600, "8N1")) {
         return 0;
     }
@@ -94,10 +85,9 @@ int USBRelayOutput::Init(Json::Value config) {
         usleep(500000);
 
         bool foundICS = false;
-        int res = 0;
-        res = read(m_fd, &c_reply, 1);
+        int res = read(m_fd, &c_reply, 1);
         if (res == 0) {
-            LogWarn(VB_CHANNELOUT, "Did not receive a response byte from ICstation relay, unable to confirm number of relays.  Using configuration value from UI\n");
+            LogWarn(VB_CHANNELOUT, "Did not receive a response byte from ICstation relay\n");
         } else if (c_reply == 0xAB) {
             LogInfo(VB_CHANNELOUT, "Found a 4-channel ICStation relay module\n");
             m_relayCount = 4;
@@ -118,53 +108,56 @@ int USBRelayOutput::Init(Json::Value config) {
 
         if (foundICS)
             write(m_fd, &c_open, 1);
+    } else if (m_subType == RELAY_DVC_CH340) {
+        LogInfo(VB_CHANNELOUT, "Initializing CH340 USB Relay with %d channels\n", m_relayCount);
     }
 
     return ChannelOutput::Init(config);
 }
 
-/*
- *
- */
 int USBRelayOutput::Close(void) {
     LogDebug(VB_CHANNELOUT, "USBRelayOutput::Close()\n");
     closeSerialPort();
     return ChannelOutput::Close();
 }
 
-/*
- *
- */
 int USBRelayOutput::SendData(unsigned char* channelData) {
     LogExcess(VB_CHANNELOUT, "USBRelayOutput::RawSendData(%p)\n", channelData);
 
-    char out = 0x00;
-    int shiftBits = 0;
-
-    for (int i = 0; i < m_relayCount; i++) {
-        if ((i > 0) && ((i % 8) == 0)) {
-            // Write out previous byte
-            write(m_fd, &out, 1);
-            out = 0x00;
-            shiftBits = 0;
+    if (m_subType == RELAY_DVC_CH340) {
+        // CH340-specific logic: Send a 4-byte command for each relay to control its state
+        unsigned char cmd[4] = { 0xA0, 0, 0, 0 }; // Initialize the command array: byte 0 is the start flag (0xA0)
+        for (int i = 0; i < m_relayCount; i++) {  // Loop over each relay channel (1 to m_relayCount)
+            cmd[1] = i + 1;                       // Byte 1: Relay number (1-based: 1 to 8 for an 8-channel relay)
+            cmd[2] = channelData[i] ? 1 : 0;      // Byte 2: Relay state (1 for ON, 0 for OFF), based on channelData[i]
+            cmd[3] = cmd[0] + cmd[1] + cmd[2];    // Byte 3: Checksum, sum of bytes 0, 1, and 2
+            write(m_fd, cmd, 4);                  // Write the 4-byte command to the serial device (m_fd) to control the relay
+        }
+    } else {
+        // Non-CH340 (Bit or ICStation) logic: Send data as a bitstream, 8 bits per byte
+        char out = 0x00;
+        int shiftBits = 0;
+
+        for (int i = 0; i < m_relayCount; i++) {
+            if ((i > 0) && ((i % 8) == 0)) {
+                write(m_fd, &out, 1);
+                out = 0x00;
+                shiftBits = 0;
+            }
+
+            out |= (channelData[i] ? 1 : 0) << shiftBits;
+            shiftBits++;
         }
 
-        out |= (channelData[i] ? 1 : 0) << shiftBits;
-        shiftBits++;
+        if (shiftBits)
+            write(m_fd, &out, 1);
     }
 
-    // Write out any unwritten bits
-    if (shiftBits)
-        write(m_fd, &out, 1);
-
     return m_relayCount;
 }
 
-/*
- *
- */
 void USBRelayOutput::DumpConfig(void) {
     LogDebug(VB_CHANNELOUT, "USBRelayOutput::DumpConfig()\n");
     dumpSerialConfig();
     ChannelOutput::DumpConfig();
-}
+}

src/channeloutput/USBRelay.h

@@ -34,9 +34,10 @@ class USBRelayOutput : public ChannelOutput, public SerialChannelOutput {
     enum RelayType {
         RELAY_DVC_UNKNOWN,
         RELAY_DVC_BIT,
-        RELAY_DVC_ICSTATION
+        RELAY_DVC_ICSTATION,
+        RELAY_DVC_CH340
     };
 
     RelayType m_subType;
     int m_relayCount;
-};
+};