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User Case 3: An example of how to program the USB endpoints in host mode
Example 3. Programming the USB Endpoints in Host Mode
// DMA channel number. Valid values are 0, 1, 2, or 3.
int CHAN_NUM = 0;
// Fifo sizes: uncomment the desired size.
// This example uses 64-byte fifo.
// int fifosize = 0; // 8 bytes
// int fifosize = 1; // 16 bytes
// int fifosize = 2; // 32 bytes
int fifosize = 3; // 64 bytes
// int fifosize = 4; // 128 bytes
// int fifosize = 5; // 256 bytes
// int fifosize = 6; // 512 bytes
// int fifosize = 7; // 1024 bytes
// int fifosize = 8; // 2048 bytes
// int fifosize = 9; // 4096 bytes
// FIFO address. Leave 64-bytes for endpoint 0.
int fifo_start_address = 8;
// Uncomment the desired buffering. If double-buffer is selected, actual
// FIFO space will be twice the value listed above for fifosize.
// This example uses single buffer.
int double_buffer = 0; // Single-buffer
// int double_buffer = 1; // Double-buffer
// Set the following variable to the device endpoint type: CONTROL ISO BULK or IN
int device_protocol = BULK;
//int device_protocol = ISO;
//int device_protocol = INT;
// USB speeds
#define LOW_SPEED 0
#define FULL_SPEED 1
#define HIGH_SPEED 2
// TXTYPE protocol
#define CONTROL 0
#define ISO 1
#define BULK 2
#define INT 3
// For maximum packet size this formula will usually work, but it can also be
// set to another value if needed. If non power of 2 value is needed (such as
// 1023) set it explicitly.
#define FIFO_MAXP 8*(1 < < fifosize);
// Set the following variable to the device address.
int device_address = 1;
// Set the following variable to the device endpoint number.
int device_ep = 1;
// Variable used for endpoint configuration
Uint8 type = 0;
// Variable to keep track of errors
int error = 0;
// The following code should be run after resetting the attached device
// Initialize the endpoint FIFO. RX and TX will be allocated the same sizes.
usbRegs->INDEX = CHAN_NUM+1;
usbRegs->RXFIFOSZ = fifosize | ((double_buffer & 1) < < 4);
usbRegs->RXFIFOADDR = fifo_start_address;
18 Universal Serial Bus (USB) Controller SPRUGH3 – November 2008
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