USB Communication using PIC microcontrollers - Revision history

DavidMeyer at 21:57, 4 September 2012

2012-09-04T21:57:48Z

DavidMeyer at 18:17, 9 July 2012

2012-07-09T18:17:53Z

DavidMeyer: /* Processing and the HID API */

2012-07-09T18:17:06Z

Processing and the HID API

DavidMeyer: /* Processing and the HID API */

2012-07-09T17:27:51Z

Processing and the HID API

DavidMeyer: /* Demo */

2012-07-09T17:20:06Z

Demo

DavidMeyer: /* Add Application-Specific USB files */

2012-07-09T17:19:01Z

Add Application-Specific USB files

DavidMeyer at 17:00, 9 July 2012

2012-07-09T17:00:18Z

DavidMeyer at 16:41, 9 July 2012

2012-07-09T16:41:33Z

DavidMeyer at 15:17, 9 July 2012

2012-07-09T15:17:42Z

DavidMeyer: /* Add Application-Specific USB files */

2012-07-03T23:11:25Z

Add Application-Specific USB files

← Older revision		Revision as of 21:57, 4 September 2012
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	'''*Under Construction*'''

	==USB Overview==		==USB Overview==

← Older revision		Revision as of 18:17, 9 July 2012
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	Here is the API [[Media:HIDAPI.zip\|documentation]], which explains what each function does.		Here is the API [[Media:HIDAPI.zip\|documentation]], which explains what each function does.

			==Matlab and the HID API==

← Older revision		Revision as of 18:17, 9 July 2012
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	The main file includes the typical functions, setup() and draw(), as well as an openPic() function used to search the computer for a connected PIC microcontroller and open it for communication.		The main file includes the typical functions, setup() and draw(), as well as an openPic() function used to search the computer for a connected PIC microcontroller and open it for communication.

			Here is the API [[Media:HIDAPI.zip\|documentation]], which explains what each function does.

@@ Line 149: / Line 149: @@
 ==Processing and the HID API==
-To send and receive USB packets in Processing on the computer, we use a Java Native Interface library which uses C libraries to communicate via USB.  Documentation and downloads for this library can be found [http://code.google.com/p/javahidapi/ here].  Attached is the Processing sketch used to interface with the demo board described above.
+To send and receive USB packets in Processing on the computer, we use a Java Native Interface library which uses C libraries to communicate via USB.  Documentation and downloads for this library can be found [http://code.google.com/p/javahidapi/ here].  This is the [[Media:Processing_USBExample.zip|Processing sketch]] used to interface with the demo board described above.
+The code directory contains both the .jar file containing the Java library, and the .dll, .jnilib, and .so files containing the native USB libraries.  These files need to be here, but do not require editing.
+In the sketch itself, the '''USBListener''' file defines a Thread which listens to the USB port.  The function pic.read() will wait until the USB buffer is not empty, and then place the first-in data into the specified variable.  This thread is also a good place to update all state variables and send out data to the PIC using pic.write().  The '''HIDManager''' extends the HIDManager class defined in the API.  This class defines callback functions which are called whenever a device is added or removed.
+The main file includes the typical functions, setup() and draw(), as well as an openPic() function used to search the computer for a connected PIC microcontroller and open it for communication.

@@ Line 123: / Line 123: @@
 ===Demo===
-Attached here is an example project for the PIC32MX250F128B.  [[Media:USBExample.zip]]
+This [[Media:USBExample.zip|MPLABX Project Directory]] is an example project written for the PIC32MX250F128B.
 This demo communicated with the processing demo explained below, using the 28-DIP package for the pic32 and the following pinout.

@@ Line 56: / Line 56: @@
 The file attached below is a zip containing examples of these four files.  This example provides generic USB HID operation under Microchip's VendorID (1240) and a ProductID of 0, operating in USB_INTERRUPT mode (described below).
-[[Media:PIC32_USB_Files.zip]]
+[[Media:PIC32_USB_Files.zip|PIC32_USB_Files]]
 === Microchip Stack Bug Notes ===

← Older revision		Revision as of 17:00, 9 July 2012
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	==Processing and the HID API==		==Processing and the HID API==

			To send and receive USB packets in Processing on the computer, we use a Java Native Interface library which uses C libraries to communicate via USB. Documentation and downloads for this library can be found [http://code.google.com/p/javahidapi/ here]. Attached is the Processing sketch used to interface with the demo board described above.

@@ Line 120: / Line 120: @@
     }
  }
+===Demo===
+Attached here is an example project for the PIC32MX250F128B.  [[Media:USBExample.zip]]
+This demo communicated with the processing demo explained below, using the 28-DIP package for the pic32 and the following pinout.
+*Pin01 - MCLR
+*Pin03 - Configured for OC2, connected to an LED
+*Pin04 - PGED1
+*Pin05 - PGEC1
+*Pin07 - Configured for AN5, reads analog voltage from potentiometer
+*Pin08 - Vss
+*Pin09 - External Clock, running at 20MHz
+*Pin12 - Configured for digital in, reads switch state
+*Pin13 - Vdd
+*Pin15 - Vbus, connected to USB 5 Volt line
+*Pin16 - Configured for digital out, connected to an LED
+*Pin18 - Configured for OC3, connected to an LED
+*Pin19 - Vss
+*Pin20 - Vcap, 10nF capacitor to Vss
+*Pin21 - USB, D+
+*Pin22 - USB, D-
+*Pin23 - Vusb, 3.3V
+*Pin27 - AVss, 10nF capacitor to AVdd
+*Pin28 - AVdd, 3.3V
 ==Processing and the HID API==

@@ Line 98: / Line 98: @@
 USB_POLLING requires the developer to call USBDeviceTasks() manually faster than the minimum rate, whereas USB_INTERRUPT handles all timing automatically.  In the demo, we use USB_INTERRUPT to handle this timing.
+Below is some sample code in the while loop of a main function of PIC communicating via USB.
+ while(1){
+    if((USBGetDeviceState() < CONFIGURED_STATE) ||
+       (USBIsDeviceSuspended() == TRUE))
+    {
+        //Either the device is not configured or we are suspended,
+        // so we don't want to execute any USB related application code
+        continue;   //go back to the top of the while loop
+    }
+    if(!HIDRxHandleBusy(USBOutHandle))	//Check if data was received from the host.
+    {
+        //Do something with the data
+        ToSendDataBuffer[0] = ReceivedDataBuffer[0];
+        //Re-arm the OUT endpoint for the next packet
+        USBOutHandle = HIDRxPacket(HID_EP,(BYTE*)&ReceivedDataBuffer,64);
+    }
+    if(!HIDTxHandleBusy(USBInHandle)){
+        // Send out new data
+        USBInHandle = HIDTxPacket(HID_EP,(BYTE*)&ToSendDataBuffer[0],64);
+    }
+ }
 ==Processing and the HID API==