From 25730e0a843bcfea522f4a6095d66ac39b73167c Mon Sep 17 00:00:00 2001
From: MuijzerF <f.muijzer@utwente.nl>
Date: Mon, 20 Jan 2025 17:04:05 +0100
Subject: [PATCH] Added start-stop and sample rate control via Serial Commands
---
src/main.cpp | 167 ++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 158 insertions(+), 9 deletions(-)
diff --git a/src/main.cpp b/src/main.cpp
index 471f2f7..ffaa4a9 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -12,8 +12,12 @@ using namespace helpers; // contains the verbose levels from Instr
const float versionNumber = 1.1; // version displayed on boot
const uint16_t serialTimeOut = 1000; // timeout in ms
const long serialBaudrate = 115200;
+const byte numChars = 32; //maximum length of messages parsed on receive.
static uint16_t logFreqSamples = 200; // give samplecounter and summary every n samples
-const uint8_t downSampler = 16; // average n number of samples before storing. 1 = no downsampling, 2 = average two samples
+uint8_t downSampler = 16; // average n number of samples before storing. 1 = no downsampling, 2 = average two samples
+const uint8_t maxDownSampler = 128; // max number of samples to average
+const uint16_t minSampleRate = 10; // Lowest Acceptable Sample Rate
+const uint16_t maxSampleRate = 8096; // Highest Acceptable Sample Rate
const uint8_t channelCountSize = 1; // always fixed at 1 byte
const unsigned char channelCount[channelCountSize] = {0x01}; // number of active channels send to the plot, for now this is ADC. Should be 0x02 if Batt is also send.
@@ -38,7 +42,7 @@ byte sensorStatusBuffer[8];
// the task durations define the sample rate of the tasks:
-const long aquisitionTaskDuration = 125; // µs per cycle //for aquisition of sensor data
+long aquisitionTaskDuration = 125; // µs per cycle //for aquisition of sensor data
const long communicationTaskDuration = 10000; // µs per cycle //of data transmission to client via Blueooth
const uint8_t jitterMax = 10; // after this number of missed samples, the device is stopped.
int jitterCounter = 0; // amount of times the sample momement was more than one sample time off.
@@ -54,13 +58,13 @@ Task communicationTask(communicationTaskDuration, TASK_FOREVER, &communicationTa
Scheduler runner; // tasks are added to the scheduler in the setup() sequence and the scheduler is executed in main() loop.
long ADCresult;
-long ADCresultArray[downSampler];
+long ADCresultArray[maxDownSampler];
float ADCvolts;
byte *bADCvolts[4]; // 4 byte float for uScope format
float battVolts;
byte *bBattvolts[4]; // 4 byte float for uScope format
-elapsedMicros elapsedMicrosTime; //timer that can easily be reset
-
+elapsedMicros elapsedMicrosTime; //timer for aquisition
+elapsedMillis elapsedMillisTime; //timer for receiving commands
namespace buffers
{
@@ -87,12 +91,70 @@ namespace buffers
}
using namespace buffers;
+
+//read messages received, this call is blocking for as long as new data continues to arrive
+//default start and end markers are < & >, other can be defines via arguments.
+//characters between the start and end marker are parsed as commands. For example "foo<start>foo" is returned as "start"
+//maxReadTime is reserved for future use, to implement a timeout function if new characters keep comming in.
+//based on https://forum.arduino.cc/t/serial-input-basics-updated/382007
+char *receiveSerialMessage(const char startMarker = '<', const char endMarker = '>', const int maxReadTime = 100)
+{
+ static char receivedChars[numChars]; // an array to store the received data
+
+ static boolean recvInProgress = false;
+ boolean newData = false;
+ static byte index = 0;
+ char charactersRead;
+ elapsedMillisTime = 0;
+
+ //TODO: cancel while loop if new data continues to arrive
+ while (Serial.available() > 0 && newData == false && elapsedMillisTime < maxReadTime) //read until no new data is available, or maxReadTime is reached
+ {
+ charactersRead = Serial.read();
+
+ if (recvInProgress == true)
+ {
+ if (charactersRead != endMarker)
+ {
+ receivedChars[index] = charactersRead;
+ index++;
+ if (index >= numChars)
+ {
+ index = numChars - 1; //TODO: comment FM: does not seem logical to do?
+
+ helpers::printToLog("Received more characters via serial than the max array length! " + String(receivedChars), verboseLevels::error);
+ }
+ }
+ else
+ {
+ receivedChars[index] = '\0'; // terminate the string
+ recvInProgress = false;
+ index = 0;
+ newData = true;
+ }
+ }
+
+ else if (charactersRead == startMarker)
+ {
+ recvInProgress = true;
+ }
+ }
+ if (newData == true) //print the parsed command for debug purposes.
+ {
+ helpers::printToLog("Received via Serial: " + String(receivedChars), verboseLevels::info);
+ }
+
+ return receivedChars;
+}
+
+
uint32_t sampleCounter = 0;
uint32_t sampleCounterOld = 0;
uint32_t millisOld = 0;
uint8_t millisWraps = 0; // count the number of times millis() reached 2^32.
uint8_t downSampleCounter = 0; // count up each aquisition cycle
+
/*
this taks reads the sensor data at a fixed interval. Based upon the realtime example of library TaskScheduler (https://github.com/arkhipenko/TaskScheduler)
this task will be started and stopped based upon the <start> / <stop> commands received via Bluetooth.
@@ -278,8 +340,95 @@ void aquisitionTask_Callback()
// this task will be active right from the boot, and will never be stopped.
void communicationTask_Callback()
{
+ //read data from Serial
+
+ // characters between the start and end marker are parsed as commands. For example "foo<start>foo" is returned as "start"
+ const char startMarker = '<';
+ const char endMarker = '>';
+ const int maxReadTime = 100; //ms
+ char *receivedChars = receiveSerialMessage(startMarker, endMarker, maxReadTime);
+
+ if (strcmp(receivedChars, "start") == 0)
+ {
+ if (!aquisitionTask.isEnabled())
+ {
+ memset(receivedChars, 0, sizeof(receivedChars) ); // clean command buffer
+ jitterCounter = 0; // reset the counter for a clean start
+ aquisitionTask.enable();
+ helpers::printToLog("Start command received, enabled aquisitionTask (start sampling)", verboseLevels::info);
+ }
+ }
+ else if (strcmp(receivedChars, "stop") == 0)
+ {
+ if (aquisitionTask.isEnabled())
+ {
+ memset(receivedChars, 0, sizeof(receivedChars) ); // clean command buffer
+ aquisitionTask.disable();
+ helpers::printToLog("Stop command received: disabled aquisitionTask (stop sampling).", verboseLevels::info);
+ }
+ }
+ else if (strncmp(receivedChars, "SetSampleRate", 13) == 0) // command starting with "SetSampleRate", should always be followed by 4 integers, for example "SetSampleRate1000" for 1000 Hz
+ {
+ if (aquisitionTask.isEnabled())
+ {
+ helpers::printToLog("Received Set Sample Rate command, but aquisition is active!", verboseLevels::error);
+ }
+ else
+ {
+ char argument[5]; // stores the value received from the host in ASCCI text
+ memcpy(argument, &receivedChars[13], 4); // copy characters from full input command
+ argument[4] = '\0'; // termination character
+ int newSampleRate = atoi(argument);
+ helpers::printToLog("Received SetSampleRate Command: " + String(newSampleRate), verboseLevels::info);
+
+ if(newSampleRate < minSampleRate || newSampleRate > maxSampleRate)
+ {
+ helpers::printToLog("Received Set Sample Rate command is below " + String(minSampleRate) + " or above " + String(maxSampleRate), verboseLevels::error);
+ }
+ else if(newSampleRate / downSampler < minSampleRate)
+ {
+ helpers::printToLog("Received Set Sample Rate command is too low in combination with configured downsampler: " + String(downSampler), verboseLevels::error);
+ }
+ else
+ {
+ aquisitionTaskDuration = 1000000 / newSampleRate; // µs per cycle //for aquisition of sensor data
+ aquisitionTask.setInterval(aquisitionTaskDuration);
+ }
+ }
+ memset(receivedChars, 0, sizeof(receivedChars) ); // clean command buffer
+ }
+ else if (strncmp(receivedChars, "SetDownSampleRate", 17) == 0) // command starting with "SetDownSampleRate", should always be followed by 4 integers, for example "SetDownSampleRate0016" for 16 times downsample
+ {
+ if (aquisitionTask.isEnabled())
+ {
+ helpers::printToLog("Received Set DownSample Rate command, but aquisition is active!", verboseLevels::error);
+ }
+ else
+ {
+ char argument[5]; // stores the value received from the host in ASCCI text
+ memcpy(argument, &receivedChars[17], 4); // copy characters from full input command
+ argument[4] = '\0'; // termination character
+ int newDownSampleRate = atoi(argument);
+ helpers::printToLog("Received SetDownSampleRate Command: " + String(newDownSampleRate), verboseLevels::info);
+
+ if(newDownSampleRate < 1 || newDownSampleRate > maxDownSampler)
+ {
+ helpers::printToLog("Received Set Down Sample Rate command is below 1 or above " + String(maxDownSampler), verboseLevels::error);
+ }
+ else if((1000000 / aquisitionTask.getInterval()) / newDownSampleRate < minSampleRate)
+ {
+
+ helpers::printToLog("Received Set Down Sample Rate command is too low in combination with configured sample rate: " + String(1000000 / aquisitionTask.getInterval()), verboseLevels::error);
+ }
+ else
+ {
+ downSampler = newDownSampleRate; //set new down sample rate
+ }
+ }
+ memset(receivedChars, 0, sizeof(receivedChars) ); // clean command buffer
+ }
- // write data to Bluetooth
+ // write data to Serial
if (btBufferA.isBufferLocked() && btBufferB.isBufferLocked())
{
@@ -301,7 +450,7 @@ void communicationTask_Callback()
helpers::printToLog(" try to send buffer B of size (bytes): " + String(btBufferB.getPointerPosition()) + ", data: " + String(btBufferB.buffer[10]), verboseLevels::extraBuffers);
if (Serial.availableForWrite())
{
- Serial.write((uint8_t *)btBufferB.buffer, btBufferB.getPointerPosition()); // write buffer until pointer position
+ Serial.write((uint8_t *)btBufferB.buffer, btBufferB.getPointerPosition()); // write buffer until pointer position
}
btBufferB.clearBuffer(); // clear buffer B & reset pointer
}
@@ -369,8 +518,8 @@ void setup()
communicationTask.enable();
helpers::printToLog("Communication task started!", verboseLevels::info);
- aquisitionTask.enable();
- helpers::printToLog("enabled aquisitionTask (start sampling)", verboseLevels::info);
+ //aquisitionTask.enable();
+ //helpers::printToLog("enabled aquisitionTask (start sampling)", verboseLevels::info);
}
void loop()
{
--
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