From 6c83b7ed2097ded689edb4e676b82e9397339012 Mon Sep 17 00:00:00 2001
From: Tyler Kron <tylerkron@gmail.com>
Date: Sun, 29 Mar 2026 10:03:16 -0600
Subject: [PATCH] fix: send decimal channel mask instead of binary string

The firmware's SCPI_ParamInt32 parses ENAble:VOLTage:DC as a decimal
integer, but the example app was treating --channels as a binary string
and generating binary masks internally.

Changes:
- IsValidChannelMask: now validates decimal integers instead of 0/1 strings
- Auto-generated all-channel mask: uses (1 << count) - 1 instead of
  new string('1', count) which produced the wrong decimal value
- Help text: updated to show decimal bitmask examples

Tested on real hardware (Nq1 at /dev/cu.usbmodem101): --channels 7
correctly logged only channels 0,1,2 (3 analog values per sample).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 Program.cs | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/Program.cs b/Program.cs
index cd55f2c..9f951a3 100644
--- a/Program.cs
+++ b/Program.cs
@@ -725,7 +725,7 @@ private static async Task<int> RunSdCardOperationAsync(CliOptions options)
                     var adcCount = streamingDevice.Metadata.Capabilities.AnalogInputChannels;
                     if (adcCount > 0)
                     {
-                        channelMask = new string('1', adcCount);
+                        channelMask = ((1u << adcCount) - 1).ToString();
                     }
                 }
 
@@ -1289,15 +1289,7 @@ private static string GetLogFormatLabel(string fileName)
 
     private static bool IsValidChannelMask(string channelMask)
     {
-        foreach (var value in channelMask)
-        {
-            if (value != '0' && value != '1')
-            {
-                return false;
-            }
-        }
-
-        return true;
+        return uint.TryParse(channelMask, out _);
     }
 
     private static void PrintHelp()
@@ -1322,7 +1314,7 @@ private static void PrintHelp()
         Console.WriteLine("Streaming Options:");
         Console.WriteLine($"  --rate <hz>              Streaming rate in Hz (default: {DefaultRate}).");
         Console.WriteLine($"  --duration <seconds>     Duration to stream (default: {DefaultDurationSeconds}).");
-        Console.WriteLine("  --channels <mask>        Enable ADC channels with a 0/1 mask.");
+        Console.WriteLine("  --channels <mask>        Enable ADC channels with a decimal bitmask (e.g. 7 = ch 0,1,2).");
         Console.WriteLine("  --limit <count>          Stop after N stream messages.");
         Console.WriteLine("  --min-samples <count>    Require at least N stream messages (exit code 2 on failure).");
         Console.WriteLine();