Digilent FX12 - Manual (Page 14)

Digilent
FX12 Reference Manual
www.digilentinc.com
Copyright Digilent, Inc. Page 14/18 Doc: 502-046
LCD Write Cycle
tsu
th
th
tw
tr
tf
tsu1 th1
tc
R/ W
RS
E
DB0- DB7
The LCD connections to the Virtex-4 are shown below. Note the LCD uses a 4-bit data interface, and
the same FPGA pins that connect to the data bus are shared with the pushbutton inputs.
FX12 LCD Circuit Diagram
Serial Port
The FX12 provides an RS-232 based serial port for user data transfers and embedded processor debug
operations. RS-232 level translation is provided by an Intersil ICL3232 transceiver.
LCD Bus Timings
Parameter Symbol Min Max Unit Test Pin
Enable cycle time tc 500 ns E
Enable High pulse width tw 220 ns E
Enable rise/fall time tr, tf 25 ns E
RS, R/W setup time tsu 40 ns RS, R/W
RS, R/W hold time th 10 ns RS, R/W
Read data output delay td 60 120 ns DB0-DB7
Read data hold time tdh 20 ns DB0-DB7
Write data setup time tsu1 40 ns DB0-DB7
Write data hold time th1 10 ns DB0-DB7