Multi-tone display device

A display module, comprising:

• a control circuit to output a horizontal clock signal and a parallel clock signal for transferring display data of M dots in one clock period, where M is an integer number not less than two;
• a converter circuit which receives the display data of M dots in serial and convert it to output the display data in parallel in accordance with said parallel clock signal;
• a first latch circuit to latch and output said display data of M dots in parallel in accordance with said parallel clock signal;
• a second latch circuit to latch and output the display data outputted from said first latch circuit in accordance with said horizontal clock signal;
• a voltage generating circuit to generate tone voltages in different tone levels according to a plurality of tones;
• a selecting circuit to select the tone voltage having a level corresponding to the display data outputted from said second latch circuit among said plurality of tone voltages in different tone levels generated by said voltage generating circuit;
• a scanning circuit to output a scanning signal;
• and
• a display panel to receive the selected tone voltage via a first signal line and to receive said scanning signal via a second signal line.