CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support
One Wire Communication Protocol
Goto page Previous  1, 2
 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
ckielstra



Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands

View user's profile Send private message

PostPosted: Sun Dec 13, 2009 5:16 pm     Reply with quote
Anonymous wrote:
Rolling my own has had a LOT of advantages,especially being hacker proof.
I'm happy for you the system has not been tampered with (as far as you know of) but your protection sounds like 'security through obscurity', not the best known protection scheme.
Guest
PostPosted: Sun Dec 13, 2009 5:48 pm     Reply with quote
Actually the system is quite robust and hacker proof(has to be to get ULC AA rating).Since it monitors for shorts between both main and backup conductors as well as grounds to Mother Earth. Also the hardware and software protocols do NOT conform to ANY known standard(RS232,485,ethernet,cable modems,cell phones, etc.)
Slap a 'sniffer' on the wires and I know about it, where and when. As well I can isolate your location and allow nodes ahead and behind to still communicate with the host. Something that 'normal' serial is incapable of. IE. ground RS-485 bus and you're compromised...me , I keep on working.

Jay
creative_35



Joined: 02 Jan 2007
Posts: 15

View user's profile Send private message

PostPosted: Sun Dec 13, 2009 8:53 pm     Reply with quote
Thanks for the comments,
ckielstra wrote:
Not sure what you mean by 'communication up on request',


I meant, The Master PIC sends a request to slave (Pull up or Pull down the bus) and while getting request, Slave sends a data to master.

ckielstra wrote:

The only questions remaining are:
- What is the distance to the receiving PIC?
- Will there be only a single PIC listening, or multiple?
- What is the desired baudrate?


The distance may vary from 10 meter to 50 meter.
Only the master pic listens.
Baudrate is not critical.

Master PIC have to do so many functions and busy always. While Master PIC need data, it will send a request to slave and listen for the reply. Master can wait only 10ms. Slave is ready to send data always. The data to be tranferred one time is 128 bit wide.
Thankyou
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

View user's profile Send private message

PostPosted: Mon Dec 14, 2009 12:06 am     Reply with quote
If 10 ms includes the data transmission, the UART speed must be at least 19k2. Not very comfortable for a software UART.
Because the communication is basically unidirectional, it could use a hardware UART as ckielstra mentioned. The
pin configuration has to be changed dynamically to allow passing of the request. But hardware UART doesn't work for PIN_C1.

Software UART is the only way for the receiver in this case, you have tune your application to make it work. Perhaps
the receiver can disable interrupts during reception period?
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group