From e3abcb64f324f85fa7c10d139dc0fe20b03d80fa Mon Sep 17 00:00:00 2001
From: James Devine <devine.jd@gmail.com>
Date: Sun, 18 Dec 2016 18:10:28 +0100
Subject: [PATCH]

---
 CPiThreshold.ino | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 CPiThreshold.ino

diff --git a/CPiThreshold.ino b/CPiThreshold.ino
new file mode 100644
index 0000000..ceaa82c
--- /dev/null
+++ b/CPiThreshold.ino
@@ -0,0 +1,52 @@
+#include <Wire.h>
+
+//this test works when testing with boards 1 and 2
+//set the threshold as a 1 time value, max is 3.3V (voltage reference removed from protos)
+//crashes due to 50Hz noise
+//input thresholds not checked 100%
+//minimum input signal duration 40ns for coincidence.
+//at 40ns incident coincidence the output lasts for 150ns - plenty for the DUE to capture.
+//Hardware is more reliable than DUE's noise immunity.
+//Note the MAX5387LAUD+ doesn't support I2C readback.
+
+//detailed threshold calibration could be done, but our signal generator doesn't plug in very well.
+//using DAC would be a nice option for checking the thresholds.
+byte ADCval;
+
+void setup() {
+  // put your setup code here, to run once:
+  pinMode(35, OUTPUT); //setup for the MAX5387 - later set to 0. signal PA0
+  pinMode(36, OUTPUT);//setup for the MAX5387 - later set to 0. signal PA1
+  pinMode(37, OUTPUT);//setup for the MAX5387 - later set to 0. signal PA2
+  pinMode(A1, INPUT); //make sure the input pins are in high impedance mode
+  pinMode(A2, INPUT);//make sure the input pins are in high impedance mode
+  digitalWrite(35, LOW);//configure the address of the MAX5387 pot
+  digitalWrite(36, LOW);//configure the address of the MAX5387 pot
+  digitalWrite(37, LOW);//configure the address of the MAX5387 pot
+  pinMode(5, INPUT); //set the interrupt pin for trigger as high impedance, probably not required
+  
+  //setup the serial for debug
+  Serial.begin(9600);
+  //setup the MAX5387 pot
+  ADCval = byte(0x00);
+}
+
+
+void loop() {
+  Wire.begin();
+  //Serial.print("MAX5387 Address ");
+  //Serial.print(0x28, HEX);
+  Wire.beginTransmission(byte(0x28)); // transmit to device #112
+  Wire.write(byte(B00010011));
+  Wire.write(ADCval);// sets register pointer to echo #1 register (0x02)
+  Wire.endTransmission();      // stop transmitting
+  Serial.print("Setpoint:"); //note that this is manually updated by the human!
+  Serial.print(ADCval); //note that this is manually updated by the human!
+  Serial.print("; A1:"); //note that this is manually updated by the human!
+  Serial.print(analogRead(A1));
+  Serial.print("; A2:"); //note that this is manually updated by the human!
+  Serial.print(analogRead(A2));
+  Serial.println(";"); //note that this is manually updated by the human!
+  delay(1000);
+  ADCval++;
+}
\ No newline at end of file