| ??? 01/09/07 16:33 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#130515 - LCD interface Responding to: ???'s previous message |
Ralph Sac said:
How do use the wr rd E strobe for LCD when their is none on 89c4051. All I want to do is make a smaller microcontroller unit to do the same thing. What it does is it teaches you how to program any LCD that works like Hitachi type display. If you look at 80c31 in url I posted pin 16 goes to a 2 input nand gate of wr. And pin 17 rd goes to the other input of nand gate. Output goes to E strobe on the LCD. The 89c4051 is core part to 80c31 2 ports instead of 4 ports. The 89c4051 uses 4k flash memory. Except that 89c4051 is smaller 20 pin and 80c31 is 40 pin they function the same. The source code is 25 pages but well commented. Yikes, that interface is old-skool. As others have said, your micro doesn't have the external-memory interface. the main problem is that the Hitachi LCD interface was designed to talk to a Motorola 68xx interface; the give-away is the presence of the E clock. See here for my LCD page. I do an 8-bit LCD interface in a Silicon Labs 8051 variant. The main point is that you have to toggle E for the proper amount of time. It's this toggling that loads the stuff on the LCD's DB[7:0] into the thing during a write (R/W low) or causes the LCD to drive its data (R/W high). My code points out the couple of SiLabs-specific details (mostly regarding port direction). Port assignments are arbitrary. -a |
