TFT LCD modules are among the most popular devices in a number of microcontroller projects especially serial port modules because they take few I/O pins and their usage is generally simple. In this tutorial we look at how to interface the 2.4″ TFT LCD touch display with the ILI9341 driver with Arduino.
This is not just a LCD break but also includes an SD card slot.It’s a 240 x 320 pixels resolution, 2.4 inch TFT LCD screen with touch ability and uses the ILI9341 driver The display uses serial interface and is controlled by 5 wires (CS, RS, SCL, SDA, RST) . The SD card also uses hardware SPI interface (CS / MOSI / MISO / SCK).
The SPI module’s pin can only input a 3.3V high level, while the Arduino output has a high level of 5V. However this display module is not 5V tolerant.
This problem can be overcome by connecting the Arduino and the display module through an external level conversion module, so that The 5V high level of the Arduino output is converted to 3.3V by the level conversion module and then input to the display module. In case you don’t have such a conversion module you can just use some 10K resistors as shown in the schematic below.
A number of libraries have been developed to ease the use of this 2.4″ TFT LCD touch screen display with Arduino. However I found a number of interesting libraries with examples that can help beginners understand the working of this display at www.lcdwiki.com. I have shown how to download and use these resources in a video at the end of this tutorial.
From the above link you can get LCDWIKI_GUI.h, LCDWIKI_SPI.h and LCDWIKI_TOUCH.h libraries which are important for controlling the 2.4″ TFT LCD touch screen using ILI9341 drivers. You can use the example below to test the display.
mylcd.Draw_Rectangle(i,(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2+i,mylcd.Get_Display_Width()-1-i,mylcd.Get_Display_Height()-(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2-i);
mylcd.Fill_Rectangle(0,(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2,mylcd.Get_Display_Width()-1,mylcd.Get_Display_Height()-(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2);
mylcd.Draw_Rectangle(i,(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2+i,mylcd.Get_Display_Width()-1-i,mylcd.Get_Display_Height()-(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2-i);
mylcd.Fill_Rectangle(i,(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2+i,mylcd.Get_Display_Width()-1-i,mylcd.Get_Display_Height()-(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2-i);
mylcd.Draw_Round_Rectangle(i,(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2+i,mylcd.Get_Display_Width()-1-i,mylcd.Get_Display_Height()-(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2-i,8);
mylcd.Fill_Round_Rectangle(i,(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2+i,mylcd.Get_Display_Width()-1-i,mylcd.Get_Display_Height()-(mylcd.Get_Display_Height()-mylcd.Get_Display_Width())/2-i,8);
When the above code is uploaded to the Arduino, different graphics will be shown on the TFT display. You may observe that the graphics move slowly and this is because the processing power of 8 bit Arduino uno is only 2Kb of RAM which is low for driving a display with high resolution. Therefore we may need a more powerful microcontroller to drive this display.
We can use the code below to test the touch functionality.When this code is uploaded to the Arduino we can be able to use a touch pen to write on the screen using text of different colors and thickness.
To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder Adafruit_ILI9341. Check that the Adafruit_ILI9341 folder contains Adafruit_ILI9341.cpp and Adafruit_ILI9341.
Place the Adafruit_ILI9341 library folder your arduinosketchfolder/libraries/ folder. You may need to create the libraries subfolder if its your first library. Restart the IDE
Spice up your Arduino project with a beautiful touchscreen display shield with built in microSD card connection. This TFT display is 2.4" diagonal and colorful (18-bit 262,000 different shades)! 240x320 pixels with individual pixel control. As a bonus, this display has a optional capacitive touch panel and resistive touch panel with controller XPT2046 attached by default.
The shield is fully assembled, tested and ready to go. No wiring, no soldering! Simply plug it in and load up our library - you"ll have it running in under 10 minutes! Works best with any classic Arduino (UNO/Due/Mega 2560).
Of course, we wouldn"t just leave you with a datasheet and a "good luck!" - we"ve written a full open source graphics library at the bottom of this page that can draw pixels, lines, rectangles, circles and text. We also have a touch screen library that detects x,y and z (pressure) and example code to demonstrate all of it. The code is written for Arduino but can be easily ported to your favorite microcontroller!
If you"ve had a lot of Arduino DUEs go through your hands (or if you are just unlucky), chances are you’ve come across at least one that does not start-up properly.The symptom is simple: you power up the Arduino but it doesn’t appear to “boot”. Your code simply doesn"t start running.You might have noticed that resetting the board (by pressing the reset button) causes the board to start-up normally.The fix is simple,here is the solution.
The ILI9341 TFT module contains a display controller with the same name: ILI9341. It’s a color display that uses SPI interface protocol and requires 4 or 5 control pins, it’s low cost and easy to use. The resolution of this TFT display is 240 x 320 which means it has 76800 pixels. This module works with 3.3V only and it doesn’t support 5V (not 5V tolerant).
The ILI9341 TFT display board which is shown in the circuit diagram above has 14 pins, the first 9 pins are for the display and the other 5 pins are for the touch module.
As mentioned above, the ILI9341 TFT display controller works with 3.3V only (power supply and control lines). The display module is supplied with 5V that comes from the Arduino board. This module has a built-in 3.3V regulator which supplies the display controller with 3.3V from the 5V source.
To connect the Arduino to the display module, I used voltage divider for each line which means there are 5 voltage dividers. Each voltage divider consists of 2.2k and 3.3k resistors, this drops the 5V into 3V which is sufficient.
The first library is a driver for the ILI9341 TFT display which can be installed from Arduino IDE library manager (Sketch —> Include Library —> Manage Libraries …, in the search box write “ili9341” and choose the one from Adafruit).
The ILI9341 TFT display is connected to Arduino hardware SPI module pins (clock and data), the other pins which are: CS (chip select), RST (reset) and DC (data/command) are defined as shown below:
The following Arduino code is from Adafruit ILI9341 library (graphicstest.ino) with some modifications in order to work with the above circuit diagram.
The component TFT supports a 2.8 inch TFT display with a resolution of 240*320 pixels.The display is not soldered on the board, but there is a 14 pin connector for a TFT display. The ILI9341 has been tested.
There are four sample projects for the Arduino IDE which could be downloaded: TFT-Box3D (download here), TFT-Graphic-Test (download here), TFT-HelloWorld (download here) and TFT-HowToUseFonts (download here). And there are two examples for the Arduino IDE for using the touch functionality which could be downloaded: TFT-TouchBtn (download here) and TFT-TouchDraw (download here).
There are two dip switches for the component: SW311 and SW314. If you want to use the TFT display all switches on SW311 have to be on on. If you additonally want to use the touchpad of the display all switch of SW314 have to be on. The following two tables shows the functions and the potential conflicts with other components
After the download it"s necessary to add both libraries to your Arduino IDE. Open Sketch > Include Library > Add .ZIP Library ... and select the downloaded archive. Do it for both libraries.
There are four sample projects for the Arduino IDE which could be downloaded: TFT-Box3D (download here), TFT-Graphic-Test (download here), TFT-HelloWorld (download here) and TFT-HowToUseFonts (download here).
And there are two examples for the Arduino IDE for using the touch functionality which could be downloaded: TFT-TouchBtn (download here) and TFT-TouchDraw (download here).
I don"t know whether this is possible or not but is there any way that I can run something similar to Android on a normal TFT. I want to make complex graphics but can"t program those complex programs using the Adafruit TFT library.
I"m still waiting for the last few components to arrive before I can build the controller, however one thing I wanted to do first is test my chosen LCD with the Teensy microcontroller. I"ve never used a TFT LCD with Arduino or Teensy before, so I first wanted to make sure that I could get the desired functionality and performance out of the LCD.
The LCD I am using is a 2.4" 320x240 TFT LCD with a ILI9341 controller chip which appears to be based off of an Adafruit design, which can be used with a Teensy-optimised Adafruit_ILI9341 library for better performance.
I decided to use the Teensy-optimised Adafruit_ILI9341 library over the standard Adafruit_ILI9341 library due to the demonstrated increased frame rate and performance of the former. I downloaded the library from the Github page and followed the provided instructions to install it into the Arduino software.
After a quick online search I couldn"t find any decent tutorials on using the LCD"s Arduino library to draw shapes (which is mostly what I want the LCD to do), however after dissecting the example sketches that come with the library it became quite clear how to do it. The best source to find out what functionality is provided is the library"s main header file, which shows all the functions that library provides such as drawRect, fillRect, fillCircle, and many more.
To test the LCD and Arduino library I decided to attempt to create a simple Teensy sketch that draws eight sliders on the LCD that each change their value from a MIDI CC message received over USB-MIDI - something that the final controller software will need to do.
I used a 3.3V 8MHz Arduino Pro Mini to drive the display - also sourced very cheaply on Ebay. I chose this board because, although the seller of this display claims that it will work at both 5v and 3.3v, the majority of these display will not. So, rather than have to use level shifters of resistor dividers, I made the whole project run at 3.3v.
//Author Danny van den brande.#include "DHT.h"#include // Core graphics library#include // Hardware-specific library#include // BEGIN CLOCK#include //clock module DS1302#include //Need for clock module#define DS1302_SCLK_PIN 21// Arduino pin for the Serial Clock//PIN 21 (SCLK_PIN) = CLK on CLOCK and SCL on arduino#define DS1302_IO_PIN 20// Arduino pin for the Data I/O//PIN 20 (IO_PIN) = DAT on CLOCK and SDA on arduino#define DS1302_CE_PIN 19// Arduino pin for the Chip Enable//PIN 19 (CE_PIN) = RST on CLOCK and TX1 on arduino for this you can define any free Digital pin.#define bcd2bin(h,l) (((h)*10) + (l))#define bin2bcd_h(x) ((x)/10)#define bin2bcd_l(x) ((x)%10)#define DS1302_SECONDS 0x80#define DS1302_MINUTES 0x82#define DS1302_HOURS 0x84#define DS1302_DATE 0x86#define DS1302_MONTH 0x88#define DS1302_DAY 0x8A#define DS1302_YEAR 0x8C#define DS1302_ENABLE 0x8E#define DS1302_TRICKLE 0x90#define DS1302_CLOCK_BURST 0xBE#define DS1302_CLOCK_BURST_WRITE 0xBE#define DS1302_CLOCK_BURST_READ 0xBF#define DS1302_RAMSTART 0xC0#define DS1302_RAMEND 0xFC#define DS1302_RAM_BURST 0xFE#define DS1302_RAM_BURST_WRITE 0xFE#define DS1302_RAM_BURST_READ 0xFF#define DS1302_D0 0#define DS1302_D1 1#define DS1302_D2 2#define DS1302_D3 3#define DS1302_D4 4#define DS1302_D5 5#define DS1302_D6 6#define DS1302_D7 7#define DS1302_READBIT DS1302_D0// READBIT=1: read instruction// Bit for clock (0) or ram (1) area,// called R/C-bit (bit in address)#define DS1302_RC DS1302_D6// Seconds Register#define DS1302_CH DS1302_D7// 1 = Clock Halt, 0 = start// Hour Register#define DS1302_AM_PM DS1302_D5// 0 = AM, 1 = PM#define DS1302_12_24 DS1302_D7// 0 = 24 hour, 1 = 12 hour// Enable Register#define DS1302_WP DS1302_D7// 1 = Write Protect, 0 = enabled#define DS1302_ROUT0 DS1302_D0#define DS1302_ROUT1 DS1302_D1#define DS1302_DS0 DS1302_D2#define DS1302_DS1 DS1302_D2#define DS1302_TCS0 DS1302_D4#define DS1302_TCS1 DS1302_D5#define DS1302_TCS2 DS1302_D6#define DS1302_TCS3 DS1302_D7// Bit for reading (bit in address)#define DS1302_READBIT DS1302_D0// READBIT=1: read instruction#define DHTPIN 16// what pin we"re connected to#define DHTTYPE DHT11// DHT 11#define DS1302_READBIT DS1302_D0// READBIT=1: read instruction#define LCD_CS A3// Chip Select goes to Analog 3#define LCD_CD A2// Command/Data goes to Analog 2#define LCD_WR A1// LCD Write goes to Analog 1#define LCD_RD A0// LCD Read goes to Analog 0#define LCD_RESET A4// Can alternately just connect to Arduino"s reset pin// Assign human-readable names to some common 16-bit color values:#define BLACK 0x0000#define BLUE 0x001F#define RED 0xF800#define GREEN 0x07E0#define CYAN 0x07FF#define MAGENTA 0xF81F#define YELLOW 0xFFE0#define WHITE 0xFFFF// OBJECTS LCD ET DHTAdafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);DHT dht(DHTPIN, DHTTYPE);float hprev, tprev, hicprev;int moisture = 0;int moisture1 = 0;int moisture2 = 0;int moisture3 = 0;int moisture4 = 0;int moisture5 = 0;int sensorValue1;int sensorValue2;int sensorValue3;int sensorValue4;int sensorValue5;int sensorValue;int relay = 35;int relay1 = 36;int relay2 = 37;int relay3 = 38;int relay4 = 39;int relay5 = 40;// Structure for the first 8 registers.// These 8 bytes can be read at once with// the "clock burst" command.// Note that this structure contains an anonymous union.// It might cause a problem on other compilers.typedef struct ds1302_struct{uint8_t Seconds:4; // low decimal digit 0-9uint8_t Seconds10:3; // high decimal digit 0-5uint8_t CH:1; // CH = Clock Haltuint8_t Minutes:4;uint8_t Minutes10:3;uint8_t reserved1:1;union{struct{uint8_t Hour:4;uint8_t Hour10:2;uint8_t reserved2:1;uint8_t hour_12_24:1; // 0 for 24 hour format} h24;struct{uint8_t Hour:4;uint8_t Hour01:1;uint8_t AM_PM:1; // 0 for AM, 1 for PMuint8_t reserved2:1;uint8_t hour_12_24:1; // 1 for 12 hour format} h12;};uint8_t Date:4; // Day of month, 1 = first dayuint8_t Date10:2;uint8_t reserved3:2;uint8_t Month:4; // Month, 1 = Januaryuint8_t Month10:1;uint8_t reserved4:3;uint8_t Day:3; // Day of week, 1 = first day (any day)uint8_t reserved5:5;uint8_t Year:4; // Year, 0 = year 2000uint8_t Year10:4;uint8_t reserved6:7;uint8_t WP:1; // WP = Write Protect};void setup(){ds1302_struct rtc;Serial.begin(9600);// Serial.println(F("BLUECORE TECH"));pinMode (relay, OUTPUT);pinMode (relay1, OUTPUT);pinMode (relay2, OUTPUT);pinMode (relay3, OUTPUT);pinMode (relay4, OUTPUT);pinMode (relay5, OUTPUT);// digitalWrite (relay, HIGH);#ifdef USE_ADAFRUIT_SHIELD_PINOUT// Serial.println(F("Using Adafruit 2.8\" TFT Arduino Shield Pinout"));#else// Serial.println(F("Using Adafruit 2.8\" TFT Breakout Board Pinout"));#endif// Serial.print("TFT size is "); Serial.print(tft.width()); Serial.print("x"); Serial.println(tft.height());//tft.reset();uint16_t identifier = tft.readID();if(identifier == 0x9325) {// Serial.println(F("Found ILI9325 LCD driver"));} else if(identifier == 0x9327) {// Serial.println(F("Found ILI9327 LCD driver"));} else if(identifier == 0x9328) {// Serial.println(F("Found ILI9328 LCD driver"));} else if(identifier == 0x7575) {// Serial.println(F("Found HX8347G LCD driver"));} else if(identifier == 0x9341) {// Serial.println(F("Found ILI9341 LCD driver"));} else if(identifier == 0x8357) {// Serial.println(F("Found HX8357D LCD driver"));} else if(identifier == 0x0154) {// Serial.println(F("Found S6D0154 LCD driver"));}tft.begin(identifier);iniText();dht.begin();//CLOCK MODULE START// Start by clearing the Write Protect bit// Otherwise the clock data cannot be written// The whole register is written,// but the WP-bit is the only bit in that register.DS1302_write (DS1302_ENABLE, 0);// Disable Trickle Charger.DS1302_write (DS1302_TRICKLE, 0x00);// Remove the next define,// after the right date and time are set.// #define SET_DATE_TIME_JUST_ONCE //= 300)digitalWrite (relay, HIGH); //TURN ON/OFF OFF RELAY 0 for watering pumpelsedigitalWrite (relay, LOW);//SENSOR 1 set your sensor here!}// OPTIONAL SENSORS PLACES FOR VALUES ON SCREEN BEGINif (sensorValue) {tft.setTextSize(2);tft.setCursor(98, 127);tft.setTextColor(GREEN);tft.fillRect(93,117,67,34,BLACK);tft.println (moisture1/1.01);if (sensorValue1 >= 300)digitalWrite (relay1, HIGH); //TURN ON/OFF OFF RELAY 1 for watering pumpelsedigitalWrite (relay1, LOW);//SENSOR 2 set your sensor here!}if (sensorValue) {tft.setTextSize(2);tft.setCursor(98, 164);tft.setTextColor(GREEN);tft.fillRect(93,154,67,34,BLACK);tft.println (moisture2/1.01);if (sensorValue2 >= 300)digitalWrite (relay2, HIGH); //TURN ON/OFF OFF RELAY 2 for watering pumpelsedigitalWrite (relay2, LOW);//SENSOR 3 set your sensor here!} // BEGIN SECTION 2 - right sectionif (sensorValue) {tft.setCursor(10,60);tft.setTextSize(2);//tft.println ("BODEM VOCHT%");tft.setCursor(256, 90);tft.setTextColor(GREEN);tft.fillRect(250,80,67,34,BLACK);tft.println (moisture3/1.01);if (sensorValue3 >= 300)digitalWrite (relay3, HIGH); //TURN ON/OFF OFF RELAY 3 for watering pumpelsedigitalWrite (relay3, LOW);//SENSOR 4 set your sensor here!}if (sensorValue) {tft.setCursor(10,60);tft.setTextSize(2);//tft.println ("BODEM VOCHT%");tft.setCursor(256, 127);tft.setTextColor(GREEN);tft.fillRect(250,117,67,34,BLACK);tft.println (moisture4/1.01);if (sensorValue4 >= 300)digitalWrite (relay4, HIGH); //TURN ON/OFF OFF RELAY 4 for watering pumpelsedigitalWrite (relay4, LOW);//SENSOR 5 set your sensor here!}if (sensorValue) {tft.setCursor(10,60);tft.setTextSize(2);//tft.println ("BODEM VOCHT%");tft.setCursor(256, 164);tft.setTextColor(GREEN);tft.fillRect(250,154,67,34,BLACK);tft.println (moisture5/1.01);if (sensorValue5 >= 300)digitalWrite (relay5, HIGH); //TURN ON/OFF OFF RELAY 5 for watering pumpelsedigitalWrite (relay5, LOW);//SENSOR 6 set your sensor here!}// OPTIONAL SENSORS PLACES ON SCREEN ENDif (hprev != h) {tft.setCursor(10, 25);tft.setTextSize(3);tft.setTextColor(CYAN);tft.fillRect(3,25,103,25,BLACK);tft.print(h);hprev = h;}if (tprev != t) {tft.setCursor(118, 25);tft.setTextSize(3);tft.setTextColor(RED);tft.fillRect(111,25,101,25,BLACK);tft.print(t);tprev = t;}if (hicprev != hic) {tft.setCursor(225, 25);tft.setTextSize(3);tft.setTextColor(YELLOW);tft.fillRect(217,25,100,25,BLACK);tft.print(hic);hicprev = hic;}ds1302_struct rtc;char buffer[80]; // the code uses 70 characters.// Read all clock data at once (burst mode).DS1302_clock_burst_read( (uint8_t *) &rtc);//+++++++++++ BEGIN TEXT CLOCK TEXT+++++++++++tft.setTextSize(2);tft.setTextColor(GREEN);tft.setCursor(13, 220);tft.fillRect(3,215,115,25,BLACK);sprintf( buffer, "%02d:%02d:%02d ", \bcd2bin( rtc.h24.Hour10, rtc.h24.Hour), \bcd2bin( rtc.Minutes10, rtc.Minutes), \bcd2bin( rtc.Seconds10, rtc.Seconds));tft.print(buffer);tft.setTextSize(1);tft.setTextColor(BLACK);tft.setCursor(127, 218);tft.fillRect(122,215,195,25,GREEN);sprintf(buffer, "%d,%d," \"Dag %d van week,%d", \bcd2bin( rtc.Date10, rtc.Date), \bcd2bin( rtc.Month10, rtc.Month), \rtc.Day, \2000 + bcd2bin( rtc.Year10, rtc.Year));tft.println( buffer);tft.setTextSize(1);tft.setTextColor(BLACK);tft.setCursor(127, 230);// tft.fillRect(122,215,194,25,GREEN);sprintf(buffer, "%d,%d," \"Day %d of week,%d", \bcd2bin( rtc.Month10, rtc.Month), \bcd2bin( rtc.Date10, rtc.Date), \rtc.Day, \2000 + bcd2bin( rtc.Year10, rtc.Year));tft.println( buffer);//+++++++++++ EINDE CLOCK +++++++++++if(timeStatus() != timeSet) {tft.setTextSize(1.5);tft.setTextColor(BLACK);tft.setCursor(28, 198);///ERROR TEXT need to be coded correctlytft.fillRect(3,191,157,19,RED);//tft.print(F("CLOCK ERROR: SYNC!"));// return micros() - start;delay(1000);}}unsigned long iniText() {// unsigned long start = micros();tft.fillScreen(BLACK);tft.setRotation(3);tft.setTextSize(1);tft.setTextColor(WHITE);tft.setCursor(15,5);tft.println("Humidity %");tft.setCursor(119,10);tft.println("Temperature oC");tft.setCursor(235,5);tft.println("Heat Index"); //Gevoels temperatuurtft.setCursor(122,2);tft.println ("BlueCore TECH"); //Put your NAME here COMPANY NAMEtft.setCursor(190,198);tft.println ("ArduinoSensors.NL"); //Put your NAME here COMPANY NAME website//TEXT SENSORStft.setCursor(10,90);tft.setTextColor(WHITE);tft.println ("SENSOR:1");tft.setCursor(10,127);tft.println ("SENSOR:2");tft.setCursor(10,164);tft.println ("SENSOR:3");tft.setCursor(170,90);tft.println ("SENSOR:4");tft.setCursor(170,127);tft.println ("SENSOR:5");tft.setCursor(170,164);tft.println ("SENSOR:6");// end TEXT SENSORS//Interface DESIGN BEGINtft.fillRect(0,0,345,1,WHITE); //Top line header whitetft.fillRect(0,19,345,2,WHITE); //Top line header 2 whitetft.fillRect(0,20,345,5,BLACK); //Top line header blacktft.fillRect(106,0,5,50,WHITE); //center vertical line header lefttft.fillRect(212,0,5,50,WHITE); //center vertical line header righttft.fillRect(0,50,345,5,WHITE); //bottom line header.tft.fillRect(160,78,5,135,WHITE);//center vertical linetft.fillRect(317,0,5,240,WHITE);//center vertical line righttft.fillRect(0,0,3,240,WHITE);//center vertical line lefttft.fillRect(0,210,345,5,WHITE);//BOTTOM LINE Footertft.fillRect(118,215,4,25,WHITE);//BOTTOM LINE Footer2 vertical smalltft.fillRect(0,210,345,5,WHITE);//BOTTOM LINE Footertft.fillRect(0,78,345,2,WHITE);//top line center screentft.fillRect(0,115,345,2,WHITE);//line 2 center screentft.fillRect(0,152,345,2,WHITE);//line 3 center screentft.fillRect(0,189,345,2,WHITE);//line 4 center screen//Interface DESIGN END// return micros() - start;}void DS1302_clock_burst_read( uint8_t *p)///BEGIN CLOCK MODULE PART2{int i;_DS1302_start();// Instead of the address,// the CLOCK_BURST_READ command is issued// the I/O-line is released for the data_DS1302_togglewrite( DS1302_CLOCK_BURST_READ, true);for( i=0; i<8; i++){*p++ = _DS1302_toggleread();}_DS1302_stop();}// --------------------------------------------------------// DS1302_clock_burst_write//// This function writes 8 bytes clock data in burst mode// to the DS1302.//// This function may be called as the first function,// also the pinMode is set.//void DS1302_clock_burst_write( uint8_t *p){int i;_DS1302_start();// Instead of the address,// the CLOCK_BURST_WRITE command is issued.// the I/O-line is not released_DS1302_togglewrite( DS1302_CLOCK_BURST_WRITE, false);for( i=0; i<8; i++){// the I/O-line is not released_DS1302_togglewrite( *p++, false);}_DS1302_stop();}// --------------------------------------------------------// DS1302_read//// This function reads a byte from the DS1302// (clock or ram).//// The address could be like "0x80" or "0x81",// the lowest bit is set anyway.//// This function may be called as the first function,// also the pinMode is set.//uint8_t DS1302_read(int address){uint8_t data;// set lowest bit (read bit) in addressbitSet( address, DS1302_READBIT);_DS1302_start();// the I/O-line is released for the data_DS1302_togglewrite( address, true);data = _DS1302_toggleread();_DS1302_stop();return (data);}// --------------------------------------------------------// DS1302_write//// This function writes a byte to the DS1302 (clock or ram).//// The address could be like "0x80" or "0x81",// the lowest bit is cleared anyway.//// This function may be called as the first function,// also the pinMode is set.//void DS1302_write( int address, uint8_t data){// clear lowest bit (read bit) in addressbitClear( address, DS1302_READBIT);_DS1302_start();// don"t release the I/O-line_DS1302_togglewrite( address, false);// don"t release the I/O-line_DS1302_togglewrite( data, false);_DS1302_stop();}// --------------------------------------------------------// _DS1302_start//// A helper function to setup the start condition.//// An "init" function is not used.// But now the pinMode is set every time.// That"s not a big deal, and it"s valid.// At startup, the pins of the Arduino are high impedance.// Since the DS1302 has pull-down resistors,// the signals are low (inactive) until the DS1302 is used.void _DS1302_start( void){digitalWrite( DS1302_CE_PIN, LOW); // default, not enabledpinMode( DS1302_CE_PIN, OUTPUT);digitalWrite( DS1302_SCLK_PIN, LOW); // default, clock lowpinMode( DS1302_SCLK_PIN, OUTPUT);pinMode( DS1302_IO_PIN, OUTPUT);digitalWrite( DS1302_CE_PIN, HIGH); // start the sessiondelayMicroseconds( 4); // tCC = 4us}// --------------------------------------------------------// _DS1302_stop//// A helper function to finish the communication.//void _DS1302_stop(void){// Set CE lowdigitalWrite( DS1302_CE_PIN, LOW);delayMicroseconds( 4); // tCWH = 4us}// --------------------------------------------------------// _DS1302_toggleread//// A helper function for reading a byte with bit toggle//// This function assumes that the SCLK is still high.//uint8_t _DS1302_toggleread( void){uint8_t i, data;data = 0;for( i = 0; i <= 7; i++){// Issue a clock pulse for the next databit.// If the "togglewrite" function was used before// this function, the SCLK is already high.digitalWrite( DS1302_SCLK_PIN, HIGH);delayMicroseconds( 1);// Clock down, data is ready after some time.digitalWrite( DS1302_SCLK_PIN, LOW);delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns// read bit, and set it in place in "data" variablebitWrite( data, i, digitalRead( DS1302_IO_PIN));}return( data);}// --------------------------------------------------------// _DS1302_togglewrite//// A helper function for writing a byte with bit toggle//// The "release" parameter is for a read after this write.// It will release the I/O-line and will keep the SCLK high.//void _DS1302_togglewrite( uint8_t data, uint8_t release){int i;for( i = 0; i <= 7; i++){// set a bit of the data on the I/O-linedigitalWrite( DS1302_IO_PIN, bitRead(data, i));delayMicroseconds( 1); // tDC = 200ns// clock up, data is read by DS1302digitalWrite( DS1302_SCLK_PIN, HIGH);delayMicroseconds( 1); // tCH = 1000ns, tCDH = 800nsif( release && i == 7){// If this write is followed by a read,// the I/O-line should be released after// the last bit, before the clock line is made low.// This is according the datasheet.// I have seen other programs that don"t release// the I/O-line at this moment,// and that could cause a shortcut spike// on the I/O-line.pinMode( DS1302_IO_PIN, INPUT);// For Arduino 1.0.3, removing the pull-up is no longer needed.// Setting the pin as "INPUT" will already remove the pull-up.// digitalWrite (DS1302_IO, LOW); // remove any pull-up}else{digitalWrite( DS1302_SCLK_PIN, LOW);delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns}}///////////////////////////// END CLOCK MODULE part 2}
Ms.Josey 
Ms.Josey