Universal Serial Bus Controller User's Guide

www.ti.com Introduction
User Case 2: An example of how to program the USB Endpoints in peripheral mode
Example 2. Programming the USB Endpoints in Peripheral 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
// 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 = 0;
// The following code should be run after receiving a USB reset from the host.
// 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;
usbRegs->TXFIFOSZ = fifosize | ((double_buffer & 1) < < 4);
usbRegs->TXFIFOADDR = fifo_start_address + (1 < < (fifosize+double_buffer));
usbRegs->RXMAXP = FIFO_MAXP;
usbRegs->TXMAXP = FIFO_MAXP;
// Force Data Toggle is optional for interrupt traffic. Uncomment if needed.
// CSL_FINS(usbRegs->PERI_TXCSR,USB_PERI_TXCSR_FRCDATATOG,1);
// Uncomment below to configure the endpoint for ISO and not respond with a
// handshake packet.
// CSL_FINS(usbRegs->PERI_RXCSR,USB_PERI_RXCSR_ISO,1);
// CSL_FINS(usbRegs->PERI_TXCSR,USB_PERI_TXCSR_ISO,1);
// After receiving a successful set-address command, set the following register
// to the specified address immediately following the status stage.
usbRegs->FADDR = device_address;
SPRUGH3 – November 2008 Universal Serial Bus (USB) Controller 17
Submit Documentation Feedback