AY0438 Display Driver

[mark_s]

I have a Glass type display with a Microchip AY0438 display driver. I found the assembly code for this chip on Microchips site, but I'm bot very good with assembly. Can anyone offer a code example of how to use this chip with PBP? I have used the LCDOUT comand with the 44780 type displays, but i have not used this type of display before.

Thanks,

Terry

Hi Terry,

I used the shiftout command. Sorry I don't have an example on this
PC. I will look for some code I have and post it later.

Mark

[rsocor01]

tallen,

Yes, I have used this chip before. The LCDOUT command is for alphanumeric LCD displays, for example a 16x2 characters display. This chip AY0438 is to drive 7-segments LCD displays. What type of display do you want to drive?

Robert

[tallen]

Its a 7 seg LCD that has a Microchip AY0438 driver with it.

Terry

[rsocor01]

Its a 7 seg LCD that has a Microchip AY0438 driver with it.

Terry

Then, you need to look at the datasheet of the LCD with the AY0438 in it. Look at figure 4 of the AY0438 datasheet. This figure shows you how to control the 32 segments. If I remember correctly, you have to connect the LCD(Phi) to the clocking signal for it to work. How many digits does the LCD have?




Robert

[mark_s]

Its a 7 seg LCD that has a Microchip AY0438 driver with it.

Terry

Terry,

Try this code. It is for a 4 digit seven segment display.

Mark

[tallen]

i'm struggling with this code. It is a 4 digit 7 segment display. The display just seems to roll continiously very fast. I put in a pause to slow it down. I removed the "IF Total = 9999 then Temp = 0" and the "Temp=Temp+1. I put it TEMP = 1234 hoping to dispaly 1234, but all I see is just jumbled up numbers. I put in TEMP = 1 and see PPP. As you can Tell I don't understand this lookup and shiftout code. Any Ideas?

Thanks,

Terry

[rsocor01]

i'm struggling with this code. It is a 4 digit 7 segment display. The display just seems to roll continiously very fast. I put in a pause to slow it down. I removed the "IF Total = 9999 then Temp = 0" and the "Temp=Temp+1. I put it TEMP = 1234 hoping to dispaly 1234, but all I see is just jumbled up numbers. I put in TEMP = 1 and see PPP. As you can Tell I don't understand this lookup and shiftout code. Any Ideas?

Thanks,

Terry

Did you wire the 7-segment LCD display to the AY0438 chip? If they came together as you said earlier, do you have the datasheet for this part? More than likely, the wiring that mark_s used in his program is different than the way you are wiring it. You need to know how the segment pins in the AY0438 are connected to the segments in the LCD display. You need the part datasheet.

Robert

[tallen]

Yes, the display is already wired to the driver chip. I will check the data sheets for both. I have the data sheet for the driver, but I will have to find the one for the LCD.

This display and driver chip was on an old product that i did not design (obviously). We have tons of these new prewire display boards that I was hoping to use on a new design. I have the original asm code for the old product, but since I'm not very good with asm, I was trying to use it with purely basic code.

Thanks,

Terry