Digilent Genesys 2 - USB HID Host

by the USB controller that is input to the FPGA. In asynchronous mode data transfer is happening on transitions of read and
write control signals. The USB controller emulates a FIFO memory, providing status signals about the availability of data to be
read or free space for data to be written. The FPGA controls data transfer by read, write and output enable signals.
Signal
Direction
(FPGA) Description
D[7:0] I/O Data bus.
RXF# Input When low, data is available for reading from the FIFO.
TXE# Input When low, data can be written to the FIFO.
RD# Output A low-pulse triggers data to be read out from the FIFO.
WR# Output A low-pulse triggers data to be written to the FIFO.
SIWU# Input Send immediate or Wake-up function. In normal mode a low pulse triggers sending a data
packet with the data currently in the FIFO, even if below the normal packet size. In suspend
mode a low pulse can wake up the Host PC.
OE# Output When low, the data bus is driven by the USB controller (read transfer). When high, the bus is
driven by the FPGA (write transfer).
CLKO Input 60
MHz () clock used in synchronous mode. Data is launched and can be captured on the rising
edge.
Table 6. DPTI signal description.
For more information, see the
FT2232H datasheet (http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf).
An industry-standard SPI interface can also be used for transferring data. It uses only four signals for serial full-duplex
communication. The USB controller acts as a SPI master, with the FPGA taking the slave role. The USB controller initiates a
transaction after
API () function calls and transfers data in both directions simultaneously.
Signal Direction (FPGA) Description
SCK Input Data bus.
MOSI () Output When low, data is available for reading from the FIFO.
MISO () Input When low, data can be written to the FIFO.
SS Input A low-pulse triggers data to be read out from the FIFO.
Table 7. DSPI signal description.
For more information, see the
FT2232H datasheet (http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf).
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10.2. Serial Peripheral Interface (DSPI)
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11. USB HID Host
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