an extension of the spi?

[mombasa]

I'm trying to make a giant scoreboard display driven by a max7219. The pic that drives the max7219 with a spi is placed on a card that is about 10 meters away. How can I take these signals so far?. Thanks to those who want to help me.

[Charles Linquis]

I would probably run the signals (at both ends) to an RS-485 driver and receiver. Run in full-duplex mode. This increases the number of wires required, but should guarantee signal quality - even if there is an offset between the grounds of the two ends. Add the termination resistors also. The datasheet for the 485 chip that you use will explain that.

[mombasa]

Charles thanks for your interest, I had thought about using a MAX485 to transmit data, but I do not know how to do because the signals being transmitted are three. Can I use three MAX485? Thanks & Regards

[Charles Linquis]

Yes, you can use 3 chips. There are some dual devices out there as well. It would take two of those.

[mombasa]

Thanks Charles for your help

[falingtrea]

The CS signal may not need a differential driver since it is static during the SPI transfer. So you would need 2 differnetial transmitters and 1 receiver on the source end and two recievers and 1 transmitter on the destination side for bidirectional transfers. The CS can be just a regular buffer chip, like a 74HC125.