User guide

CY3687 MoBL-USB FX2LP18 Development Kit User Guide, Doc. # 001-68582 Rev. *B 25
Development Board
U4 has the group address 0100 and is strapped to unit address 001. Therefore to write a value to the
7-segment readout, 8051 firmware sends a control byte of 01000010 (the LSB indicates a write
operation), followed by the data byte.
U2 uses its I/O pins as inputs connected to S1-S4 according to the following table:
U2 has the group address 0100, and is strapped to unit address 000. Therefore to read the switch
values, 8051 firmware sends a control byte of 01000001 (the LSB indicates a read operation), and
then reads the data byte.
3.8 LED Indicators
LEDs D1, D2, and D4 indicate available power on the three power rails (3.3 V, 2.5 V, and 1.8 V).
LED D3 indicates drive activity on the ATA connector. LED D5 indicates that the debugger is active.
Bit Switch
0 S1
1 S2
2 S3
3 S4