AN1048

LCD demo board

19/21

5.2

Power supply

The LCD demo board should be supplied by a maximum DC voltage of 5V. The board is

provided with the connector JP1 for this board supply.

Note:

For the demo software loaded inside the micro, the board should be supplied with 5V. The

software attached to this application note displays the word “EMBEDDED” and tunes

automatically its contrast from transparent to dark with the ST software pattented method.

The Vrms increase is performed by putting the segment voltage once at Vdd, once at -Vdd

during the dead times, the Vrms decrease is performed by putting at 0 the segment voltage

during the same dead times. The voltage average is then kept. Refer to the software

attached to this application note for more details.

5.3

Programming

The demo board uses the ST72F321B microcontroller and can be programmed using the

ICC protocol. The board is provided with the ICC connnector JP2. By default, OSC_TYP is

programmed as a resonator oscillator in the option bytes. You can disable the option bytes

when you want to use the ICC clock to program the micro.

5.4

Reset

The device can be reset by pressing the switch s1 on the demo board.

5.5

Oscillation system

The demo board is mounted with a 16 MHz crystal with 8 MHz fcpu. You can change this

clock value but need to modify the timer setting inside the software accordingly.