From 0282f200a3e0236f5baca9d3fd9db2fb2b66c5e6 Mon Sep 17 00:00:00 2001
From: Ludovic Pouzenc <ludovic@pouzenc.fr>
Date: Sun, 13 Jun 2021 13:01:31 +0200
Subject: MyOBD: Trace every read and write to OBD adapter, lpo.ino: adapt for
 tracing

Extra for future : cap readDTC() call frequency to not struggle the CAN bus
---
 lpo/MyOBD.h | 12 ++++++++++++
 lpo/lpo.ino | 26 ++++++++++++++++----------
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/lpo/MyOBD.h b/lpo/MyOBD.h
index ea143be..f2124c3 100644
--- a/lpo/MyOBD.h
+++ b/lpo/MyOBD.h
@@ -1,8 +1,20 @@
 #ifndef __MYOBD_H
 #define __MYOBD_H
 #include <OBD.h>
+
+#include <MyLCD.h>
+extern MyLCD lcd;
+
 class MyOBD : public COBDI2C {
   public:
+  void write(const char* s) {
+    lcd.print("<<<"); lcd.println(s);
+    COBDI2C::write(s);
+  }
+  byte receive(char* buffer, byte bufsize, int timeout) {
+    byte res = COBDI2C::receive(buffer,bufsize, timeout);
+    lcd.print(">>>"); lcd.println(buffer);
+  }
   /* Fake OBD for testing
   int i;
   MyOBD() {
diff --git a/lpo/lpo.ino b/lpo/lpo.ino
index 85a595b..b85de2b 100644
--- a/lpo/lpo.ino
+++ b/lpo/lpo.ino
@@ -2,38 +2,36 @@
 * Inpired from simple_obd_display.ino by Stanley Huang <stanley@freematics.com.au>
 * (Simple OBD Data Display for Freematics OBD-II Adapter)
 *************************************************************************/
-#include "MyLCD.h"
+#include <MyLCD.h>
 #include "MyOBD.h"
-
 MyLCD lcd;
 MyOBD obd;
 
 void setup()
 {
   lcd.begin();
-  lcd.print("obd.begin()");
+  lcd.println("obd.begin()");
   obd.begin();
-  lcd.println(" done");
   reconnect();
   showDTC();
+  while(1); // Freeze exec here for now
   initScreen();
 }
 
 void reconnect()
 {
-  lcd.setCursor(1,2);
-  lcd.print("obd.init()                       ");
-  lcd.setCursor(11,2);
+  lcd.println("obd.init()");
   while (!obd.init()) {
-    lcd.print(".");
+    lcd.println("obd.init() failed");
   }
-  lcd.println(" done");
 }
 
 void showDTC() {
   static char buf[10];
   static uint16_t codes[16];
-  byte c, count = obd.readDTC(codes, 16);
+  byte c, count;
+  lcd.println("obd.readDTC()");
+  count = obd.readDTC(codes, 16);
   lcd.print("DTC: ");
   if ( count==0 ) {
     lcd.println("none");
@@ -50,8 +48,16 @@ void loop()
 {
   static byte pids[]= {PID_RPM, PID_SPEED, PID_ENGINE_LOAD, PID_THROTTLE};
   static byte index = 0, prev_err=obd.errors;
+  static long prevRead = 0;
+  long wait;
   byte pid = pids[index];
   int value;
+
+  // Don't read on CAN bus to fast, it struggle and reset main car dashboard
+  wait = millis() - prevRead + 25; // 40 Hz, 10 FPS for 4 pids
+  if ( wait > 0 ) delay(wait);
+  prevRead = millis();
+
   // send a query to OBD adapter for specified OBD-II pid
   if (obd.readPID(pid, value)) {
       showData(pid, value);
-- 
cgit v1.2.3