Post by thread:Protocol

> I'm searching to for such a protocol too. Ofcourse it's not very difficult > to make one my own, but i think it's far better to use a well known > standard. But I haven't found it yet. I'm still looking in the 'home > automation' world, were there are standards as X10 and CE-bus. But they tell > you very little about the protocol itself. The 9-bit protocol i've seen too. > It sounds smart only the thing is that i want to be able to control my slave > devices (mostly ofcourse PIC-devices) with a visual basic program on a PC. > As far a i know 9-bit communications not supported. There is a company called Cimetrics that has software tools for 9bit networking for all the popular micros as well as the PC. You can even do it with the usual 8250 UART by playing with MARK and SPACE parity on a 8 bit word, detecting the address and command bytes is a bit of a pain as you have to use either EVEN or ODD parity and check what the parity of the byte was and check if you got a parity error, best to use the PC for a single master system. > It's pretty straigth forward. It's inportant that al the slave listen in > sync to the master. Then they know wether the package is adressed for them > or for another-slave. If the slave is out-of- sync, it will try to sync on > the first 0x55 it encounters. If this happens halfway a package, the > checksum will prevent the slave of taking. The change the slave will take > action on WRONG data is very little, but NOT zero! > > I'm very curious to other protocols. So if you or anyone knows a good widely > used protocol consisting of LITTLE!! packages, I'm one big ear! There are various Internet Protocols that may be suitable, I will start using UDP packets in my next broadcast transmission system, they have a a header of about 40 bytes but it is possible to ship them over a IP network if you put in a router (i286 + serial card + ether card + PC Route sw) and then you can get your data into a computer anywhere on the planet. I'll post something on the list when I get it working. Cheers -- Kalle Pihlajasaari spam_OUTkalleTakeThisOuTdata.co.za Interface Products Box 15775, Doornfontein, 2028, South Africa +27 (11) 402-7750 Fax: +27 (11) 402-7751