topic Re: LCD HC08 in 8-bit Microcontrollers

LCD HC08

ppcco — Wed, 22 Feb 2006 05:27:16 GMT

Hi, I need a routine writed in c to control an LCD 2*16, I'm using HC908QT4, somebody can help me?

Regards

Re: LCD HC08

eckhard — Wed, 22 Feb 2006 08:20:01 GMT

Hello,

what language are you using. For C look at AN2940 and for assembler look at AN1745.

Eckhard

Re: LCD HC08

bigmac — Wed, 22 Feb 2006 14:26:28 GMT

Hello ppco,

If your LCD display is the conventional parallel interface type, there won't be sufficient I/O available on the QT4 device for simple direct connection of the display - as a minimum you would likely need the QY4 device.

With 4-bit parallel (nybble) interface, you will need a minimum of 6 lines from the device, all output capable. With 8-bit parallel interface a minimum of 10 lines are needed. The code is somewhat more complex for the 4-bit mode.

The number of pins required could potentially be reduced with an intervening shift register device between the MCU and the display - requiring a more complex circuit configuration and again, more complex code.

Regards,

Mac

Re: LCD HC08

eckhard — Wed, 22 Feb 2006 16:27:11 GMT

Hello,

a pcf8574 with a software I2C interface will do the job using two I/O Pins.

Eckhard

Re: LCD HC08

yb — Thu, 23 Feb 2006 00:10:52 GMT

... or a 74HC595, which avoid to write IIC routines...

Re: LCD HC08

Encoder — Thu, 23 Feb 2006 10:59:44 GMT

"If your LCD display is the conventional parallel interface type, there won't be sufficient I/O available on the QT4 device for simple direct connection of the display - as a minimum you would likely need the QY4 device"

Definitely right!!

The other suggestions are only theoretical: any addition of an external periferal like a shift register or an iic translator upsets any small difference in price between QT4 and QY4, far increasing difficulty in programming and complicating the hardware.