Generic_HID Firmware for Microchip Full-speed USB Chips
Using Microchip MCHPFSUSB Framework v2.3

Jan Axelson
www.Lvr.com

12/24/08

V1.4
See generic_hid.c for project history

PROJECT DESCRIPTION

This firmware is for a generic HID USB device (not a system 
keyboard or mouse) that does the following:

Receives Output reports using interrupt OUT transfers and sends the report 
data back to the host in Input reports using interrupt IN transfers.

Receives Output reports using control transfers (Set_Report request) and 
sends the report data back to the host in Input reports using control transfers 
(Get_Report requests.)

Receives Feature reports using control transfers (Set_Report request) and 
sends the report data back to the host in Feature reports using control transfers 
(Get_Report requests.)

A single buffer holds received Feature reports and reports to be sent.

The firmware is adapted from Microchip's Mouse example.

The project has been tested on the PICDEM™ FS USB DEMONSTRATION BOARD


MORE INFORMATION

This application, host applications to communicate with the device, and more about 
USB and HIDs are available from:

www.Lvr.com/hidpage.htm


HOW TO CREATE THE PROJECT

Download and install the Microchip MCHPFSUSB Framework v2.3. 

Try this location for the Framework:
 
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2651&param=en534494

The installation creates a directory structure under "Microchip Solutions", 
assuming you use the default directory.

The zip file that contains this readme file also contains a project directory 
for the Generic HID application. The directory is:

USB Device - Generic HID

Copy this directory as a subdirectory of the Microchip Solutions directory 
so you end up with:

Microchip Solutions\USB Device - Generic HID

STACK CHANGES

You'll also need to make some additions to three of the USB stack files in 
Microchip Solutions\Microchip. 

The changes support some additional HID-specific capabilities and shouldn't 
affect other Microchip examples.  

1. In usb_device.c:

Add line 4 (hid_report_feature) in this block:

#if defined(USB_USE_HID)
    volatile unsigned char hid_report_out[HID_INT_OUT_EP_SIZE];
    volatile unsigned char hid_report_in[HID_INT_IN_EP_SIZE];
    volatile unsigned char hid_report_feature[EP0_BUFF_SIZE];  
#endif

2. In usb_device.h:

Add line 5 (hid_report_feature) in this block:

#if defined(USB_USE_HID)
    //class specific data buffers
    extern volatile unsigned char hid_report_out[HID_INT_OUT_EP_SIZE];
    extern volatile unsigned char hid_report_in[HID_INT_IN_EP_SIZE];
    extern volatile unsigned char hid_report_feature[EP0_BUFF_SIZE];    
#endif		


3. In usb_function_hid.c:

Replace the empty functions HIDGetReportHandler and HIDSetReportHandler with these:

/********************************************************************
 * Function:        void HIDGetReportHandler(void)
 *
 * PreCondition:    A Setup packet with a HID Get_Report request
 *                  has been received.
 *
 * Input:           None
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Overview:        If the HID supports the requested report, provides data 
 *                  for an Input or Feature report. Otherwise configures
 *                  the endpoint to return STALL.
 *
 * Note:            None
 *******************************************************************/
void HIDGetReportHandler(void)
{
	inPipes[0].info.bits.busy = 1;
	inPipes[0].info.Val = USB_INPIPES_RAM | USB_INPIPES_BUSY | USB_INPIPES_INCLUDE_ZERO;
	
	if ((SetupPkt.W_Value.byte.HB) == 0x01)	
	{
		// Input report
	
		if (SetupPkt.W_Value.byte.LB == 0x00)				
		{			
			// Report ID = 0
			inPipes[0].pSrc.bRam = (BYTE*)&hid_report_in;
            inPipes[0].wCount.Val = HID_INPUT_REPORT_BYTES;
		}
		else 
		{
			// Stall unsupported report IDs.

			pBDTEntryIn[0]->STAT.Val = _USIE|_BSTALL;
		}
	}

	else if (SetupPkt.W_Value.byte.HB == 0x03)
	{
		// Feature report
	
		if (SetupPkt.W_Value.byte.LB == 0x00)		
		{
			// Report ID = 0

			inPipes[0].pSrc.bRam = (BYTE*)&hid_report_feature;
           	inPipes[0].wCount.Val = HID_FEATURE_REPORT_BYTES;
		}
		else 
		{
			// Stall unsupported report IDs.

			pBDTEntryIn[0]->STAT.Val = _USIE|_BSTALL;
		}
	}
	else 
	{
		// Stall unsupported report types.

		pBDTEntryIn[0]->STAT.Val = _USIE|_BSTALL;
	}
 
}//end HIDGetReportHandler

/********************************************************************
 * Function:        void HIDSetReportHandler(void)
 *
 * PreCondition:    A Setup packet with a HID Set_Report request
 *                  has been received.
 *
 * Input:           None
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Overview:        If the HID supports the report the host is requesting
 *                  to send, prepares to receive the report in the 
 *                  Data stage of the control transfer.
 *                  Otherwise the endpoint returns STALL.
 *
 * Note:            None
 *******************************************************************/

void HIDSetReportHandler(void)
{
	switch (ReportSupported())
    {
		case 0x02: // Output report 
		{	
			outPipes[0].wCount.Val = SetupPkt.wLength;
	        outPipes[0].pDst.bRam = (BYTE*)OUTPUT_REPORT;
	        outPipes[0].pFunc = SET_REPORT_PFUNC;
	        outPipes[0].info.bits.busy = 1;
			break;
		}
		case 0x03: // Feature report 
		{	
			outPipes[0].wCount.Val = SetupPkt.wLength;
	        outPipes[0].pDst.bRam = (BYTE*)FEATURE_REPORT;
	        outPipes[0].pFunc = SET_REPORT_PFUNC;
	        outPipes[0].info.bits.busy = 1;
			break;
		}
		default:
		{
			// The endpoint will return STALL.

			outPipes[0].info.bits.busy = 0;
		}
	}

}//end HIDSetReportHandler

***
To include the Microchip C18 libraries in the project:
1. Select Project > Build Options > Project
2. In "Show Directories for;", select Include Search Path 
3. Click New.
4. Browse to your MCC18\h directory and add it to the Search Path List.
5. Click OK.