PIC32MX: USB Communication with a PC - Revision history

DerekSiegal: /* C Code */

2010-03-07T22:06:26Z

C Code

← Older revision		Revision as of 17:06, 7 March 2010
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	===C Code===		===C Code===
	The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This will allow you to easily get the necessary includes. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator". ~~Download~~ the whole project '''[[Media:USB - CDC Device - PIC32.zip\|here]]'''.		The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This will allow you to easily get the necessary includes. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator". Make sure you download the whole project by clicking '''[[Media:USB - CDC Device - PIC32.zip\|here]]''', as some of the h files are different.

	The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.		The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.

DerekSiegal: /* C Code */

2010-03-07T22:04:58Z

C Code

← Older revision		Revision as of 17:04, 7 March 2010
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	===C Code===		===C Code===
	The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This will allow you to easily get the necessary includes. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".		The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This will allow you to easily get the necessary includes. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator". Download the whole project '''[[Media:USB - CDC Device - PIC32.zip\|here]]'''.

	The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.		The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.

NickMarchuk at 20:19, 1 March 2010

2010-03-01T20:19:32Z

← Older revision		Revision as of 15:19, 1 March 2010
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	== Original Assignment ==

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

	Your assignment is to set up the PIC32 to send and receive data with a PC using the USB communications device class (USB CDC).

	This type of communication will allow you to talk to a virtual serial port on a PC, just like using the RS232 cable, except you will communicate with the USB cable that powers your PIC32 and achieve faster communication than you could with the RS232 cable.

	Use the example projects in the "Microchip Solutions/USB Device - CDC - Basic Demo" and "Microchip Solutions/USB Device - CDC - Serial Emulator" folders as guides.

	Send 1000 bytes of data to your PC from your PIC32 and have your PC echo them back to the PIC32. How long does it take? Does it always take the same amount of time? What if you change to a different (faster or slower) PC?

	== Overview ==		== Overview ==

DerekSiegal: /* MATLAB Code */

2010-02-16T03:54:58Z

MATLAB Code

← Older revision		Revision as of 22:54, 15 February 2010
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	"The average bit rate was 15330.950 kbits/s		"The average bit rate was 15330.950 kbits/s
	There were a total of 0 errors during the transmission"		There were a total of 0 errors during the transmission"

			This bit rate displayed by MATLAB could be different, since the USB does not have a set speed. There should always be 0 errors with a slightly variable data rate.

DerekSiegal: /* Overview */

2010-02-16T03:51:53Z

Overview

← Older revision		Revision as of 22:51, 15 February 2010
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	In the past, the RS232 cable has been used to communicate with a PC. However, the PIC32 is capable of communication through the USB cable as well. This form of data transfer is preferable for a number of reasons. First, the circuit is much simpler (in our case non-existent). Second, the speed is significantly faster. However, as you will see later on, the code associated with USB can be very complicated.		In the past, the RS232 cable has been used to communicate with a PC. However, the PIC32 is capable of communication through the USB cable as well. This form of data transfer is preferable for a number of reasons. First, the circuit is much simpler (in our case non-existent). Second, the speed is significantly faster. However, as you will see later on, the code associated with USB can be very complicated.

	The average speed of the RS232 tops out at about 100 ~~kbs~~. It was found that USB transfer can reach an average speed of about 2 ~~mbs~~, which is 20 times as fast.		The average speed of the RS232 tops out at about 100 kb/s. It was found that USB transfer can reach an average speed of about 2 mb/s, which is 20 times as fast.

	In order to send and receive 1000 bits through USB, an interface program is required. MATLAB was used in this case. The point of the following code is to sends 1000 bits 100 times. Each time 1000 bits are sent, then are echoed back to the ~~PIC~~ by the PC. It timed how long each transaction took and averaged them out. It also remembers the sequence of bits that were sent and compares them in order to determine if any mistakes were made.		In order to send and receive 1000 bits through USB, an interface program is required. MATLAB was used in this case. The point of the following code is to sends 1000 bits 100 times. Each time 1000 bits are sent, then are echoed back to the PC by the PIC. It timed how long each transaction took and averaged them out. It also remembers the sequence of bits that were sent and compares them in order to determine if any mistakes were made.

	== Circuit ==		== Circuit ==

DerekSiegal: /* C Code */

2010-02-16T02:54:47Z

C Code

← Older revision		Revision as of 21:54, 15 February 2010
Line 26:		Line 26:

	===C Code===		===C Code===
	The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".		The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This will allow you to easily get the necessary includes. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".

	The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.		The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.

DerekSiegal: /* C Code */

2010-02-16T02:53:24Z

C Code

← Older revision		Revision as of 21:53, 15 February 2010
Line 27:		Line 27:
	===C Code===		===C Code===
	The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".		The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".

			The send and receive commands are putsUSBUSART() and getsUSBUSART() respectively.

	===MATLAB Code===		===MATLAB Code===

DerekSiegal: /* C Code */

2010-02-16T02:31:39Z

C Code

← Older revision		Revision as of 21:31, 15 February 2010
Line 26:		Line 26:

	===C Code===		===C Code===
	The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator"~~. Make sure to add the NU_32 hardware profile to the workspace as well~~.		The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. Make sure to add the NU_32 hardware profile to the workspace as well. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".

	===MATLAB Code===		===MATLAB Code===

DerekSiegal: /* C Code */

2010-02-16T02:31:21Z

C Code

← Older revision		Revision as of 21:31, 15 February 2010
Line 26:		Line 26:

	===C Code===		===C Code===
	The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator".		The C code for USB communication is very extensive. The main file alone is more than 600 lines of code, and incorporates thousands more in include files. Download the main file '''[[Media:main_USB.c\|here]]'''. This main file is to be inserted into the project for the CDC device Basic Demo that was automatically installed with MPLAB. This code follows the model set by the example "Microchip Solutions/USB Device - CDC - Serial Emulator". Make sure to add the NU_32 hardware profile to the workspace as well.

	===MATLAB Code===		===MATLAB Code===

DerekSiegal: /* Circuit */

2010-02-16T02:13:46Z

Circuit

← Older revision		Revision as of 21:13, 15 February 2010
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	== Circuit ==		== Circuit ==

	[[image:USB.jpg\|thumb\|150px\|USB cable is all you need!\|right]]
	There is no circuit required for USB communication with a PC. The USB cable that powers the PIC is the same that transmits data in and out.		There is no circuit required for USB communication with a PC. The USB cable that powers the PIC is the same that transmits data in and out.