Hi!

Problem 1:
I have a problem with lcd's. We have about 101 lcd's connected to our selfmade board. Distance to last display is 4.5 metres. Displays are latched 4 or 5 times. Everything is boxed in metalcase. Flat cables are coated with alufoil. Crystal we are using is 22.1184 MHz, but when using this crystal large (6x20 lcd) display gets crazy. All other 100 (4x20) are initialized ok. We have tried all kind of delays in software, but nothing helped. First (large) display was connected to address 0x0800, but we found out that that address was allways enabled. We changed the address to 0x0801 and display wasn't active all the time, but it still screwed up.

Problem 2:
Then we changed crystal to 11.0592 and it worked fine, but we cannot use thermal printer in com port 1 (80c320 has tho ports;port 0 and port 1), because it is using 19200 baudrate and port 1 works only half of port 0 speed. I have setted only TH1, and I don't know can port 1 be setted to use another timer and how to set.

We were thinking about the gearbox discussed few days ago, but it seems quite impossible... Perhaps we could try to use ferrites for flat cable and try to ground more and better, but we are not sure if that helps. Is there any other possibilities to eliminate interferences?

Our board is designed ourself. It has 64k ROM, 64k RAM, 100+1 LCD's, 100 leds, two serial ports (port 0: RS485 and port 1:RS232), 5 ir net curtains, rf remote controller and 4x4 + 4 keyboard. Microcontroller is DS80c320. Because our project is so large, there goes a lot of flat cables and there is some interference. Shielded flat cable costs a lot so we are using unshielded cable. We have tried to use shielded pair cables as much as possible, but it is not possible everywhere. Sometimes foil seems to strenghten the interference.

If anyone has any ideas, it could help us a lot. Thanks in advance.