http://stackoverflow.com/questions/8773703/faster-usb-hid-output
but I don't understand how they are achieving that...
I read somewhere low speed USB was limited to 8bytes for interrupt transfers, at a per 10ms polling interval, that is pretty slow,
I'd like to send chunks of 32 or 64 bytes to the AVR over HID, and have the AVR respond with 8 bytes.
Using HID without drivers is important to me, so I definitely want to stick with HID methods.
but how would I modify my headers to gain the increase this person was talking about?
Currently I am using these headers....
Code: Select all
PROGMEM const char usbDescriptorHidReport[34] =
{
//[Endpoint 0]
0x06, 0xa0, 0xff, // USAGE_PAGE (Vendor Defined Page 1)
0x09, 0x01, // USAGE (Vendor Usage 1)
0xa1, 0x01, // COLLECTION (Application)
//[Endpoint 1] Interrupt-In (used to send data to the host spontaneously)
// Input Report (Host PC sends us data)
0x09, 0x02, // Usage ID - vendor defined usage2
0x15, 0x00, // Logical Minimum (0)
0x26, 0xFF, 0x00, // Logical Maximum (255)
0x75, 0x08, // Report Size (8 bits)
0x95, 0x08, // Report Count (8 fields)
0x81, 0x02, // Input (Data, Variable, Absolute)
//[Endpoint 2] Interrupt-Out (PC is sending US data)
// Output Report (We send data to PC)
0x09, 0x03, // Usage ID - vendor defined usage3
0x15, 0x00, // Logical Minimum (0)
0x26, 0xFF, 0x00, // Logical Maximum (255)
0x75, 0x08, // Report Size (8 bits)
0x95, 0x08, // Report Count (8 fields) //change to 32?
0x91, 0x02, // Output (Data, Variable, Absolute)
0xc0 // END_COLLECTION
};
//to do this you must set USB_CFG_DESCR_PROPS_CONFIGURATION in usbconfig.h
#define W(x) (x)&0xFF,(x)>>8
#define USB_CFG_RESERVED 0x80
#define USB_CFG_SELFPOWERED 0x40 //remove this for BusPowered devices
PROGMEM const char usbDescriptorConfiguration[41] =
{
//Config
9, //bLength
2, //bDescriptorType 2=CONFIG
W(41), //wTotalLength
1, //bNumInterfaces
1, //bConfigurationValue
0, //ConfigurationStrIndex
(USB_CFG_RESERVED | USB_CFG_SELFPOWERED), //ConfigAttributes
100/2, //MaxPower (in 2 Milliampere) 100 mA
//HID_Interface
9, //bLength
4, //bDescriptorType 4=INTERFACE
0, //bInterfaceNumber
0, //bAlternateSetting
2, //bTotalEndpoints
0x03, //bInterfaceClass HID_CSCP_HIDClass
0x00, //bInterfaceSubClass HID_CSCP_NonBootSubclass
0x00, //bInterfaceProtocol HID_CSCP_NonBootProtocol
0, //InterfaceStrIndex 0=NONE
//HID_GenericHID
9, //bLength
0x21, //bDescriptorType HID
1,1, //BCD representation of HID version
0, //target country code
1, //number of HID Report Descriptor infos to follow
0x22, //descriptor type: report
W(34), //total length of report descriptor
//HID_ReportIN_Endpoint
7, //Length
0x05, //bDescriptorType ENDPOINT
0x81, //bEndpointAddress ENDPOINT_DIR_IN=0x80+1
0x03, //bmAttributes INTERRUPT //0x03|(0<<2)|(0<<4)
W(8), //wMaxPacketSize
10, //Polling Interval in ms (cannot be less than 10)
//HID_ReportOUT_Endpoint
7, //Length
0x05, //bDescriptorType ENDPOINT
0x02, //bEndpointAddress ENDPOINT_DIR_IN=0x00+2
0x03, //bmAttributes INTERRUPT //0x03|(0<<2)|(0<<4)
W(8), //wMaxPacketSize
10, //Polling Interval in ms (cannot be less than 10)
};
