From d63df10f7268399b364c22ecd6046c14c418f806 Mon Sep 17 00:00:00 2001
From: Philip Lampkin <plampkin@chem.wisc.edu>
Date: Tue, 29 Dec 2020 14:57:13 -0600
Subject: Initial commit

---
 .../Slave_Random_LED_I2C/Slave_Random_LED_I2C.ino  | 120 +++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 Digital Photoreactor Controller Firmware/Test Sketchs/Slave_Random_LED_I2C/Slave_Random_LED_I2C.ino

(limited to 'Digital Photoreactor Controller Firmware/Test Sketchs/Slave_Random_LED_I2C')

diff --git a/Digital Photoreactor Controller Firmware/Test Sketchs/Slave_Random_LED_I2C/Slave_Random_LED_I2C.ino b/Digital Photoreactor Controller Firmware/Test Sketchs/Slave_Random_LED_I2C/Slave_Random_LED_I2C.ino
new file mode 100644
index 0000000..7f7a7f6
--- /dev/null
+++ b/Digital Photoreactor Controller Firmware/Test Sketchs/Slave_Random_LED_I2C/Slave_Random_LED_I2C.ino	
@@ -0,0 +1,120 @@
+
+// ---------------------------------
+// Stress test program/example for TinyWireS I2C library.
+// Run this slave program on the Attiny.
+// Run the other master program on the Arduino Uno R3.
+// ---------------------------------
+// // Written by Scott Hartog, 2/6/2016, to stress test the TinyWireS library.
+// https://github.com/rambo/TinyWire
+//
+// This project uses the Tiny85 as an I2C slave.
+//
+// The slave program using TinyWireS, running on a Attiny85, receives
+// N bytes of random data in a single receiveEvent() callback and
+// stores that data in a global buffer. It then responds the first requestEvent()
+// callback with that same data. The requestEvent() callback overwrites the data
+// buffer with zeros after responding so it will only respond correctly to the
+// first requestEvent() callback after each receiveEvent() callback. Subsequent
+// requestEvent() will respond with 0xff for all data bytes.
+//
+//
+// SETUP:
+// AtTiny Pin 5 (PB0/SDA) = I2C SDA 
+//     connect to SDA on master with external pull-up (~4.7K)
+// AtTiny Pin 7 (PB0/SCL) = I2C SCL 
+//     connect to SCL on master with external pull-up (~4.7K)
+// AtTiny Pin 1 (PB5/!RST)
+//     connect to reset on master (or just pull-up)
+//
+// Please see credits and usage for usiTwiSlave and TinyWireS in the .h files of 
+// those libraries.
+
+#include "TinyWireS.h"                  // wrapper class for I2C slave routines
+
+#define I2C_SLAVE_ADDR  0x26            // i2c slave address (38, 0x26)
+
+// global buffer to store data sent from the master.
+uint8_t master_data[16];
+// global variable to number of bytes sent from the master.
+uint8_t master_bytes;
+
+const int LEDPin = 4; //pin 4 arduino, pin 3 on ATTiny85)
+const int FanPin = 1; // pin 1 arduino, pin 6 on ATtiny85)
+
+// Gets called when the ATtiny receives an i2c write slave request
+void receiveEvent(uint8_t num_bytes)
+{
+  uint8_t i;
+  
+  // save the number of bytes sent from the master
+  master_bytes = num_bytes;
+
+  // store the data from the master into the data buffer
+  for (i = 0; i < master_bytes; i++)
+    master_data[i] = TinyWireS.receive();
+    
+    analogWrite(FanPin, master_data[0]);
+    analogWrite(LEDPin, master_data[1]);
+
+}
+
+// Gets called when the ATtiny receives an i2c read slave request
+void requestEvent()
+{
+  uint8_t i;
+  
+  // send the data buffer back to the master
+  for (i = 0; i < master_bytes; i++)
+    TinyWireS.send(master_data[i]);
+
+  // corrupt the byte values in the data buffer
+  // so that subsequent call won't match
+  for (i = 0; i < master_bytes; i++)
+    master_data[i] += 0x5a;
+
+  // corrupt length of the request, but dont' make it zero
+  
+  // if the usiTwiSlave.c is working fine, then this number is completely irrelevant
+  // because the requestEvent() callback will not be called again until
+  // after the next receiveEvent() callback, so the master_data and
+  // master_bytes variables will be set by that call.
+
+  // If the usiTwiSlave.c has the issue of calling the requestFrom() callback
+  // for each byte sent, the buffer will accumulate by this amount *for each byte
+  // in the original request*.
+  // 
+  // Making it zero will obscure the 1-byte send issue in the usiTwiSlave.c
+  // that is being tested.
+  // Making it small will allow a few requests to succeed before the tx buffer
+  // overflows and the usiTwiSlave.c hangs on the "while ( tmphead == txTail );"
+  // line
+  master_bytes = 2; 
+}
+
+void setup()
+{
+  // initialize the TinyWireS and usiTwiSlave libraries
+  TinyWireS.begin(I2C_SLAVE_ADDR);      // init I2C Slave mode
+
+  // register the onReceive() callback function
+  TinyWireS.onReceive(receiveEvent);
+  
+  // register the onRequest() callback function
+  TinyWireS.onRequest(requestEvent);
+
+  pinMode(LEDPin, OUTPUT);
+  pinMode(FanPin, OUTPUT);
+  
+  TCCR0B = TCCR0B & 0b11111000 | 0b001; // Sets internal timer to 31250 Hz, and PWM frequency on PB0 (Arduino pin 4) to 31250 Hz, fast enough for a fan!
+
+  //analogWrite(FanPin, FanPwm);
+  //analogWrite(LEDPin, LEDPwm);
+
+}
+
+void loop()
+{
+  // This needs to be here
+  TinyWireS_stop_check();  
+  // otherwise empty loop
+}
-- 
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