USB Host and Device

The DE2 board provides both USB host and device interfaces using the Philips ISP1362 single-chip USB controller. The host and device controllers are compliant with the Universal Serial Bus Specification Rev. 2.0, supporting data transfer at full-speed (12 Mbit/s) and low-speed (1.5 Mbit/s). Figure 1 shows the schematic diagram of the USB circuitry; the pin assignments for the associated interface are listed in Table 1.

Detailed information for using the ISP1362 device is available in its datasheet and programming guide; both documents can be found in the ISP1362 references below. The most challenging part of a USB application is in the design of the software driver needed. Two complete examples of USB drivers, for both host and device applications, can be found in Sections 5.3 and 5.4. These demonstrations provide examples of software drivers for the Nios II processor.

Figure 1. USB (ISP1362) host and device schematic.

Table 1. USB (ISP1362) signal assignments

Signal NameDescription
OTG_ADDR[1:0] ISP1362 Address[1:0]
OTG_DATA[15:0] ISP1362 Data[15:0]
OTG_CS_N ISP1362 Chip Select
OTG_RD_N ISP1362 Read
OTG_WR_N ISP1362 Write
OTG_RST_N ISP1362 Reset
OTG_INT0 ISP1362 Interrupt 0
OTG_INT1 ISP1362 Interrupt 1
OTG_DACK0_N ISP1362 DMA Acknowledge 0
OTG_DACK1_N ISP1362 DMA Acknowledge 1
OTG_DREQ0 ISP1362 DMA Request 0
OTG_DREQ1 ISP1362 DMA Request 1
OTG_FSPEED USB Full Speed, 0 = Enable, Z = Disable
OTG_LSPEED USB Low Speed, 0 = Enable, Z = Disable

See DE2_pin_assignments.csv, a comma-delimited file that matches "standard" descriptive names to actual FPGA pin locations. This file can be directly opened in Microsoft Excel.


   ISP1362 Universal Serial Bus Controller, datasheet
ISP1362 Embedded Programming Guide, (pdf)

   DE2 User Manual, version 1.4, 2006. (pdf)

Maintained by John Loomis, last updated 18 April 2007