PIC32MX: I2C Communication between PIC32s - Revision history

NickMarchuk at 20:17, 1 March 2010

2010-03-01T20:17:34Z

← Older revision		Revision as of 15:17, 1 March 2010
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	== Original Assignment ==

	'''Do not erase this section!'''

	Your assignment is to create code that allows two PIC32s to communicate via I2C.

	== Overview ==		== Overview ==

Thomas Peterson: /* Master Code */

2010-02-24T16:10:34Z

Master Code

← Older revision		Revision as of 11:10, 24 February 2010
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	#pragma config FPBDIV = DIV_1 //Sets PBCLK to SYSCLK		#pragma config FPBDIV = DIV_1 //Sets PBCLK to SYSCLK

	#define Fsck 50000 ~~//Frequency of (I2C) serial clock~~		#define Fsck 50000
			#define BRG_VAL ((PBCLK/2/Fsck)-2)

	#define Nop() asm( "nop" ) //No-operation; asm stands for assembly, using an assembly command in C. Cool!		#define Nop() asm( "nop" ) //No-operation; asm stands for assembly, using an assembly command in C. Cool!

JamesRein: /* Slave Code */

2010-02-16T04:45:55Z

Slave Code

← Older revision		Revision as of 23:45, 15 February 2010
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	SlaveWriteI2C1(dataRead);		SlaveWriteI2C1(dataRead);
	} else if ((I2C1STATbits.R_W == 1) && (I2C1STATbits.D_A == 1)) {		} else if ((I2C1STATbits.R_W == 1) && (I2C1STATbits.D_A == 1)) {
	// R/W bit = 1 --> indicates data transfer is ~~input~~ to slave		// R/W bit = 1 --> indicates data transfer is output from slave
	// D/A bit = 1 --> indicates last byte was data		// D/A bit = 1 --> indicates last byte was data
	mLED_0_On();		mLED_0_On();

JamesRein: /* Slave Code */

2010-02-16T04:44:53Z

Slave Code

← Older revision		Revision as of 23:44, 15 February 2010
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	} else if ((I2C1STATbits.R_W == 1) && (I2C1STATbits.D_A == 0)) {		} else if ((I2C1STATbits.R_W == 1) && (I2C1STATbits.D_A == 0)) {
	// R/W bit = 1 --> indicates data transfer is output from slave		// R/W bit = 1 --> indicates data transfer is output from slave
	// D/A bit = 1 --> indicates last byte was address		// D/A bit = 0 --> indicates last byte was address
	mLED_0_On();		mLED_0_On();
	mLED_2_Off();		mLED_2_Off();

JamesRein: /* Overview */

2010-02-16T04:39:26Z

Overview

← Older revision		Revision as of 23:39, 15 February 2010
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	== Overview ==		== Overview ==

	[http://www.nxp.com/acrobat_download/literature/9398/39340011.pdf I2C] is pronounced "I squared C" and stands for Inter-Integrated Circuit. This protocol was designed by Phillips Semiconductors around 1992 to allow easy communication between components on the same circuit board and can achieve transfer rates of up to 400 kbit/sec. Is is a 2 line (plus common ground) communication method for one master device to control up to 112 slave devices. While it is possible to have multiple masters on the same ~~I2c~~ bus, this page will only deal with a one master configuration.		[http://www.nxp.com/acrobat_download/literature/9398/39340011.pdf I2C] is pronounced "I squared C" and stands for Inter-Integrated Circuit. This protocol was designed by Phillips Semiconductors around 1992 to allow easy communication between components on the same circuit board and can achieve transfer rates of up to 400 kbit/sec. I2C is a 2 line (plus common ground) communication method for one master device to control up to 112 slave devices. While it is possible to have multiple masters on the same I2C bus, this page will only deal with a one master configuration.

	<b>Basic Operation</b>		<b>Basic Operation</b>
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	The data line can only change while the clock line is low. The data line is only read when the clock line is high and therefore 1 bit can be transferred per cycle of the clock line.		The data line can only change while the clock line is low. The data line is only read when the clock line is high and therefore 1 bit can be transferred per cycle of the clock line.

	The master is initially sends a start bit followed by the 7-bit address of the slave it wishes to communicate with. The next bit represents whether it wishes to write(0) to or read(1) from the slave.		The master initially sends a start bit followed by the 7-bit address of the slave it wishes to communicate with. The next bit represents whether it wishes to write(0) to or read(1) from the slave.

	The slave then responds with an acknowledge bit. The transmission continues according to whether the master is attempting to read to or write from the device.		The slave then responds with an acknowledge bit. The transmission continues according to whether the master is attempting to read to or write from the device.

JamesRein: /* Code */

2010-02-16T04:18:45Z

Code

← Older revision		Revision as of 23:18, 15 February 2010
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	== Code ==		== Code ==
	In the code below, the master sends one of two bytes (0xAA or 0x23) to the slave at address 0x40. The ~~slave~~ then ~~sends~~ ~~the~~ byte back. If the slave receives a 0xAA, it lights its LEDs.		In the code below, the master sends one of two bytes (0xAA or 0x23) to the slave at address 0x40. The master then receives a byte back from the slave. If the slave receives a 0xAA, it lights its LEDs.
			When the master begins sending, the slave triggers an interrupt (if the slave address is a match), which does one of four actions based on whether the master is reading or writing and whether the last byte was a data or address byte. As mentioned, when the master is writing the slave stores the byte, and when the master is reading the slave sends back the last stored byte.

	===Master Code===		===Master Code===
	/********************************************************		/********************************************************

JamesRein: /* Master Code */

2010-02-16T04:12:07Z

Master Code

← Older revision		Revision as of 23:12, 15 February 2010
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	===Master Code===		===Master Code===
	/*******************************************************		/********************************************************
	* I2C_Master.c: Master code for I2C communication. *		* I2C_Master.c: Master code for I2C communication. *
	* Both PICS use I2C1 module to send/ receive data.*		* Both PICS use I2C1 module to send/ receive data.*
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	* *		* *
	* Hardware: 2 PIC32MX460F512L PICs on NU32 boards *		* Hardware: 2 PIC32MX460F512L PICs on NU32 boards *
	*******************************************************		********************************************************
	* Thomas Peterson, James Rein, Eric West *		* Thomas Peterson, James Rein, Eric West *
	* ME333 Winter 2010 *		* ME333 Winter 2010 *

JamesRein: /* Code */

2010-02-16T04:10:40Z

Code

← Older revision		Revision as of 23:10, 15 February 2010
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	== Code ==		== Code ==
			In the code below, the master sends one of two bytes (0xAA or 0x23) to the slave at address 0x40. The slave then sends the byte back. If the slave receives a 0xAA, it lights its LEDs.

	(code description here)

	===Master Code===		===Master Code===
	/*******************************************************		/*******************************************************
	* I2C_Master.c: Master code for I2C communication. *		* I2C_Master.c: Master code for I2C communication. *
	* Both PICS use I2C1 module to send/ ~~recieve~~ data.*		* Both PICS use I2C1 module to send/ receive data.*
	* The master sends different values to a slave, *		* The master sends different values to a slave, *
	* which uses an interrupt to respond accordingly. *		* which uses an interrupt to respond accordingly. *

JamesRein: /* Overview */

2010-02-16T03:20:55Z

Overview

← Older revision		Revision as of 22:20, 15 February 2010
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	\|SCL1\|\|Serial Clock Line\|\|Output from master		\|SCL1\|\|Serial Clock Line\|\|Output from master
	\|-		\|-
	\|SDA1\|\|Data Line\|\|~~Output~~ ~~from~~ ~~master~~		\|SDA1\|\|Data Line\|\|The single data line for sending/receiving
	\|-		\|-
	\|}		\|}


	The data line is read each time the clock line goes high, as shown in the diagram below:		The data line is read each time the clock line goes high, as shown in the diagram below:

JamesRein: /* Overview */

2010-02-16T03:19:54Z

Overview

← Older revision		Revision as of 22:19, 15 February 2010
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	\|SDA1\|\|Data Line\|\|Output from master		\|SDA1\|\|Data Line\|\|Output from master
	\|-		\|-
	}		\|}

	The data line is read each time the clock line goes high, as shown in the diagram below:		The data line is read each time the clock line goes high, as shown in the diagram below: