NU32: Serial Communication with the PC - Revision history

Lynch at 11:34, 16 January 2016

2016-01-16T11:34:31Z

NickMarchuk: /* Sample Code */

2012-02-07T20:31:43Z

Sample Code

NickMarchuk: /* Sample Code */

2012-02-07T20:30:58Z

Sample Code

NickMarchuk: /* Communicating with NU32_Utility */

2012-02-01T20:59:04Z

Communicating with NU32_Utility

NickMarchuk: /* Sample Code */

2012-02-01T20:57:51Z

Sample Code

Show changes

NickMarchuk: /* Library Functions */

2012-02-01T20:48:03Z

Library Functions

Nelson Rosa: /* Details */

2012-01-30T19:25:07Z

Details

Lynch: /* Communicating with a Terminal Program */

2012-01-29T15:02:15Z

Communicating with a Terminal Program

JarvisSchultz: /* Python */

2012-01-24T16:32:42Z

Python

JarvisSchultz: /* Python */

2012-01-24T16:09:02Z

Python

← Older revision		Revision as of 11:34, 16 January 2016
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			'''THIS PAGE REFERS TO A PRE-RELEASE VERSION OF THE NU32 PIC32 DEVELOPMENT BOARD. FOR INFORMATION, SAMPLE CODE, AND VIDEOS RELATED TO THE PRODUCTION VERSION (2016 AND LATER), AND TO THE CORRESPONDING BOOK "EMBEDDED COMPUTING AND MECHATRONICS WITH THE PIC32 MICROCONTROLLER," VISIT [[NU32\|THE NU32 PAGE]].'''


	The NU32 has the ability to talk directly with a computer over a virtual serial port connection. This ability can be used to debug code, transfer data, and interact with the microcontroller using a computer.		The NU32 has the ability to talk directly with a computer over a virtual serial port connection. This ability can be used to debug code, transfer data, and interact with the microcontroller using a computer.

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 </pre>
-This function will run until the computer sends '\r' or '\n', and will put all characters received until then into charArray. Then you can use sscanf() to parse out the message in the array. For example, if message has been entered as '100 200\n' the next lines in your program might be:
+This function will run until the computer sends '\r' or '\n', and will put all characters received until then into charArray. Then you can use sscanf() to parse out the message in the array. For example, if the user entered '100 200\n', the next lines in your program might be:
 <pre>

@@ Line 55: / Line 55: @@
 </pre>
-This function will run until the computer sends '\r' or '\n', and will put all characters received until then into charArray. The you can use sscanf() to parse out the message in the array.
+This function will run until the computer sends '\r' or '\n', and will put all characters received until then into charArray. Then you can use sscanf() to parse out the message in the array. For example, if message has been entered as '100 200\n' the next lines in your program might be:
+<pre>
+int var1, var2;
+sscanf(charArray, "%d %d", &var1, &var2)
+</pre>
+Now var1 = 100 and var2 = 200.
 To receive characters in an interrupt, enable the interrupt with NU32_EnableUART1Interrupt():

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 == Communicating with NU32_Utility ==
 The right hand side of the NU32_Utility program is a debugger that will display any character received from the 'Debug' port, and will send any characters in the text entry using 'Send'.
-Compile the code and put it on your NU32. Send an 'a' with the debugger and you should see the following:
 [[Image:NU32_utility_serial_ex.png|thumb|300 px|left]]<br clear=all>

@@ Line 13: / Line 13: @@
 == Library Functions ==
-[[Media:NU32_serial_example.zip | This code]] contains functions to read characters and write strings over the serial port. It uses the same header files as "Hello World".
+[[Media:NU32SerialExample.zip | This code]] contains functions to read characters and write strings over the serial port. It uses the same header files as "Hello World".
 *NU32.c contains the functions to initialize the LEDs and USER button on the NU32 board, and to initialize the UART modules.
 *NU32.h contains function prototypes for the .c file.
@@ Line 19: / Line 19: @@
 The functions that control the serial communication are:
-*void initSerialNU32(void) - enables UART1 and UART4 at 115200 baud with an interrupt at priority level 2 and 3
+*void NU32_Initialize(void) - enables UART1 and UART4 at 115200 baud. UART4 starts with the interrupt at priority level 3, UART1 starts with no interrupt enabled
+*void NU32_EnableUART1Interrupt(void) - enables the UART1 interrupt
-*void WriteString(UART_MODULE, const char *) - call with UART1 and the character array you wish to send
-*void PutCharacter(UART_MODULE, const char) - writes an individual character to the computer when the module is able to, called by WriteString()
+*void NU32_WriteUART1(const char *) - call with the character array you wish to send, make the array with sprintf()
+*void NU32_ReadUART1(char *, int) - call with the array you want to read into, and the maximum size of the array. The code will wait at this function and buffer all characters received until you send a '\r' or '\n' (by pressing [enter] on your keyboard)
-NU32_serial_example.c in the .zip file above demonstrates how to use the functions.
+NU32SerialExample.c in the .zip file above demonstrates how to use the functions.
 == Sample Code ==

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 == Details ==
-The FT2232H chip is hardwired the to UART1 (F2 and F8, for general communication) and UART4 (D14 and D15, for bootloading) modules on the PIC32MX795F512L.  The Receive (RX) pins, F2 and D14, and Transmit (TX) pins, F8 and D15, are also brought out to the sides of the NU32 board.  '''They should not be used as general IO.'''
+The FT2232H chip is hardwired to the UART1 (F2 and F8, for general communication) and UART4 (D14 and D15, for bootloading) modules on the PIC32MX795F512L.  The Receive (RX) pins, F2 and D14, and Transmit (TX) pins, F8 and D15, are also brought out to the sides of the NU32 board.  '''They should not be used as general IO.'''
-Serial communication is asynchronous, it does not use an external clock signal to know when to read individual bits. Instead, the sender and receiver decide beforehand what frequency to transmit data. This frequency is called the baud rate and must match on both the NU32 and computer for the data to be interpreted correctly.
+Serial communication is asynchronous, it does not use an external clock signal to know when to read individual bits. Instead, the sender and receiver decide beforehand what frequency to transmit data. This frequency is called the baud rate (bits per second) and must match on both the NU32 and computer for the data to be interpreted correctly.
 The NU32 uses the UART1 and UART4 modules at 115200 baud, as does the sample code below.

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 On Windows, you can use [http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html PuTTY] or [http://realterm.sourceforge.net/index.html#downloads_Download RealTerm].
-On a MAC, you can use [http://www.iterm2.com/#/section/home iTerm2].
+On a MAC, you can try [http://homepage.mac.com/dalverson/zterm/ ZTerm].
 In Linux people commonly use [https://help.ubuntu.com/community/Minicom minicom] or [https://fedorahosted.org/gtkterm/ gtkterm].

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 Note that the argument after the "-p" will be different depending on which port the NU32 is attached to on your computer.  On a MAC it would be something like "/DEV/TTY.USBSERIAL-000030FDA" and in Linux it might be "/dev/ttyUSB0".  Also note that the "-e" argument is for turning on local echo.  In other words, when you hit a key it will show up in the output window.
+The following is a piece of sample Python code that replicates the other serial examples from above:
+<pre>
+## First we import the system module
+import sys
+## First thing that we need to do is import the serial library:
+try:
+    import serial
+except ImportError:
+    print "[FATAL] Serial library not found"
+    sys.exit(0)
+## open comm port
+com = serial.Serial('COM7',baudrate=115200)
+## send 'a' character
+com.write('a')
+print "sent 'a'"
+## read in values sent by PIC
+data = com.read(30) ## we read 30 characters because Python counts the
+                    ## \n and \r as characters
+print "Incoming data:"
+print data
+## close serial port:
+com.close()
+</pre>
 == More Information ==

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 == Python ==
+For those familiar with Python, its [http://pyserial.sf.net/ serial library] can provide several useful, platform-independent functions for interfacing with the NU32 board.  The latest installation comes with a terminal emulator written in Python called [http://pyserial.sourceforge.net/examples.html#miniterm miniterm] (source code [http://pyserial.svn.sourceforge.net/viewvc/*checkout*/pyserial/trunk/pyserial/serial/tools/miniterm.py here]).  To run miniterm with the NU32 you would run a command on the command line similar to
+<pre>
+  python miniterm.py -p COM7 -b 115200 -e
+</pre>
+Note that the argument after the "-p" will be different depending on which port the NU32 is attached to on your computer.  On a MAC it would be something like "/DEV/TTY.USBSERIAL-000030FDA" and in Linux it might be "/dev/ttyUSB0".  Also note that the "-e" argument is for turning on local echo.  In other words, when you hit a key it will show up in the output window.
 == More Information ==