Digilent 410-258P-KIT - Manual (Page 10)

Anvyl Reference Manual
www.digilentinc.com page 10 of 16
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
The FT2232HQ, attached to port J12, is also used as the controller for the Digilent USB-JTAG
circuitry, but these two functions behave entirely independent of one another. Programmers interested
in using the UART functionality of the FT2232 within their design do not need to worry about the JTAG
circuitry interfering with their data, and vice-versa.
USB HID Hosts
Two Microchip PIC24FJ128GB106
microcontrollers provide the Anvyl
with USB HID host capability.
Firmware in the microcontrollers
can drive a mouse or a keyboard
attached to the type A USB
connectors at J13 and J14 labeled
"HID" and “HOST”. Hubs are not
supported, so only a single mouse
or a single keyboard can be used
at each port.
The “HOST” PIC24 drives four
signals into the FPGA – two are dedicated as a keyboard/mouse port following the PS/2 protocol, and
two are connected to the FPGA’s two-wire serial programming port, so the FPGA can be programmed
from a file stored on a USB memory stick. To program the FPGA, attach a FAT formatted memory
stick containing a single .bit programming file in the root directory, load JP2, and cycle board power.
This will cause the PIC processor to program the FPGA, and any incorrect bit files will automatically
be rejected. Note the PIC24 reads the FPGA's mode, init, and done pins, and can drive the PROG pin
as a part of the programming sequence.
HID Controller
To access a USB host controller, EDK designs can use the standard PS/2 core (non-EDK designs
can use a simple state machine).
Fig. 10. PS/2 Timing Diagram