Receive serial data

[ruijc]

Hi all,

I have built a logger to store temperatures into an eeprom and later at home i dump all values to my PC where i can build graphs and so on.

My objective is to build an interface with a pic/eeprom/LCD where i can connect to the output of my logger and receive the data and get the math for Max, Min, Avg and check these values on site with the LCD.

I have almost everything figured up but i'm puzzled in how to receive the data.

The logger is sending the data with a loop like: reading eeprom at address x, sending that data using the debug line ( with 13,10 at the end to separate the values ) and with a speed of 9600, increment x and loop for next address.

The result is something like this:

23
28
50
75
110
115
etc

My doubt is in how will be the codeline to receive and place each temperature reading in a variable for storage. How to recognize each reading and not mixing or skip any other?

Thanks
Rui

[skimask]

What is the range of temperatures that you are going to record?

[ruijc]

Greetings Skimask

Long time no talk

The recorded temperatures from the logger are between 0 and 160ºC.

Thanks
Rui

[skimask]

The recorded temperatures from the logger are between 0 and 160ºC.

1 degree granularity (i.e. 10C 11C) or less than that (i.e. 10.2C 11.547381223430947C)?

[ruijc]

Just 1 degree granularity 10, 11, etc

.

[skimask]

Just 1 degree granularity 10, 11, etc

Well, if it was me, and I wanted close to 100% assurance that my data was good, I guess I'd go a little bit crazy and do something like have a 'packet' of X number of bytes, each packet for one temperature reading for each 'location'...

packet start ID (example of $FF)
address X.lowbyte
address X.highbyte
data byte
same data byte (inverted)
address X.highbyte (inverted)
address X.lowbyte (inverted)
packet end ID ($00, which is the packet start ID inverted)

So, I'd end up with an 8 byte packet, everything is sent, then it's all sent again but inverted at the bit level. The packet start ID might be an $FF (because the temp's will never be that high), the addresses might be that high, but if you got that then the packet end ID wouldn't match up.
It's a bit overkill, but I don't see why it would work. And really, I think I'd trust my wiring enough to just send a couple of $FF's as a start marker, then the whole recorded memory from start to finish, maybe with a couple of $FF's as an end marker.
It's all up to you. You get to make RSP... ruijc's serial protocol.