Need simple code to test PCF8577 with LC display

[The Puma]

I need simple test source code how i can drive a LC display with a PCF8577 I2C IC

Please can someone help me?

Thx

[The Puma]

Nobody can help me ?

[PCM programmer]

You're asking us to write a driver for you. Ideally, you would at least
attempt to write one yourself and then if it fails, ask for help.

[The Puma]

[Kenny]

Yes, I thought that you would have realised that the code I posted for the SAA1064 was similar to
that needed for the PCF8577, and would have been able to adapt it.
I have used it before many times in battery-powered equipment.

To get you started, here's some definitions. See data sheet.

#define PCF8577_WRITE_ADDRESS 0x74 // Same for all PCF8577 devices on bus

// Control reg. bits:
// Bit7 0/1 Display has Direct drive/Duplex drive
// Bit6 0/1 Select BankA/BankB
// Bit5 Subaddress bit A2
// Bit4 Subaddress bit A1
// Bit3 Subaddress bit A0
// Bit2 Segment byte address reg. msb
// Bit1 Segment byte address reg.
// Bit0 Segment byte address reg. lsb

// Modes. Includes i2c subaddresses.
// Subaddress bit A0 not available because the pin is used for the external
// resistor (10k to com) and capacitor (0.1uf to Vcc) connection to the internal
// backplane oscillator. In this case A0 is defined as 0.
// In Direct Drive, BP2 not used, so A2 available for subaddress.
#define MODE0 0x00 // Direct drive, using Bank A, subaddr.(A2=0,A1=0,A0=0)
#define MODE1 0x10 // Direct drive, using Bank A, subaddr.(A2=0,A1=1,A0=0)
#define MODE2 0x20 // Direct drive, using Bank A, subaddr.(A2=1,A1=0,A0=0)
#define MODE3 0x30 // Direct drive, using Bank A, subaddr.(A2=1,A1=1,A0=0)

Since all PCF8577 chips on the same bus have the same address there is no need to pass the address,
only need to send the mode.
eg.
send_pcf8577_num(MODE1,count);

and in the driver
i2c_start();
i2c_write(PCF8577_WRITE_ADDRESS);
i2c_write(mode); //Send mode byte
then the digits.
Segment handling is the same as for the SAA1064, although you may need to send the digits in a different order depending on how the lcd is wired.

[The Puma]

Thx Kenny,

now i have a start

UPDATE:

It works now

But how can i display 'COLON' between segment 2 and three?

[Kenny]

If you want the colon on permanently, connect the relevant pin on the lcd to Vcc. If you want to turn it on and off in software connect the pin on the lcd to a pin on the PCF8577 that would otherwise be used for turning a decimal point on and off.

[The Puma]