PIC24FJ128GL306 interfacing with custom LCD

[hemnath]

Hi,

Controller: PIC24FJ128GL306
Display: Attached pdf.

MPLAB X IDE, xC16 compiler

Connections as per the attached circuit.

In program, initialization routine for display,
void V_InitializeDisplay(void)
{
LCDCON = 0x000F; // 1/8 Mux (8 Com), clk = FRC,LCD Disabled in sleep,
LCDPS = 0x0000; // Type A waveform,1/3 bias, no prescaler
LCDSE0 = 0xFFFF; // Segment 0 to 15 enabled
LCDSE1 = 0x00FF; // Segments 16 to 23 enabled
LCDREF = 0x80F0; // Ref ladder in B power,high power ladder mode, max contrast
LCDREG = 0x0001; // clk source for reg = 32khz lprc, charge pump vol = AVDD
V_LCDPowerON();
}

void V_LCDPowerON(void)
{
LCDCON |= 0x8000;
}

Voltage applied to controller: 3V

Only controller and display are connected. No external circuits are connected.

Once powered ON, characters on the display is not clear(Very dull).

 

[KlausST]

Hi,

I guess there are application notes or design notes regarding "how to use LCDcontroller".
Did you read through them?

Klaus

 

[hemnath]

Yes. I have read the document. I can see SEGMENTS ON. Contrast is set high.

LCD initialization commands,
LCDCON = 0x800f; // 1/8 Mux (8 Com), clk = FRC,LCD Disabled in sleep,
LCDPS = 0x0000; // Type A waveform,1/3 bias, no prescaler
LCDSE0 = 0xFFFF; // Segment 0 to 15 enabled
LCDSE1 = 0x00FF; // Segments 16 to 23 enabled
LCDREG = 0x8001; // clk source for reg = 32khz lprc, charge pump vol = AVDD
LCDREF = 0x80F0; // Ref ladder in B power,high power ladder mode, max contrast

On the display datasheet, it is mentioned as 1/4 bias. But the controller has a maximum of 1/3 bias and it is selected. I see some segments are dull. Any suggestions.

 

[KlausST]

Hi,

You say: "some segments are dull".
But what segments are dull? Do you expect those segments to be ON or OFF?

You may use a scope (high impedance input mode) and show us some waveforms.

Best: make only one segment to be ON.
Show us folowing waveforms.
* row and column of the ON segment
* row and column of any OFF segment.

Klaus

 

[hemnath]

error in initialization commands. Now the problem is solved. I tried LPRC 32 kHz is very slow and FRC 8Mhz which is fast and consumes lot of power. I prefer to test with 1Mhz. how to change the frequency.