serial communications

Doug Shave

hello all,
I am working on a project with the basic stamp, I have multiple temp sensors on the stamp that I am reading using the 1-wire protocol; however, I also want to read serial input from another device.· My question is:
···· I am trying to get serial data into the stamp, but I am unsure about the timing.·
·The device I am using has 9600 baud, n, 8, 1.· How would I go about getting the data without any losses.
and is there a way to poll the data every so often to refresh it.

thanks,
Doug

Philip Gamblin

Would dumping the data to a serial LCD help? What Stamp are u using? Can you inititiate communication, will it wait for you to talk to it first or do you need to be listening all the time? If you need a buffer that the stamp could read when it's ready, you would have to build one. Depending on the stamp you have, 9600 baud could be a bit of a challenge. Check out the SERIN help in the BS2 editor HELP.Can you use another Stamp to handle that communication? I haven't Googled it yet but there may be a hardware soultion on the web.
·What about this device? http://www.gaoresearch.com/onlinestore/index.php?main_page=product_info&products_id=49

Post Edited (Philip Gamblin) : 7/21/2005 4:39:36 PM GMT

Larry~

If this secret device is just pumping out data then I would try
·
Serin pin, 16468,[noparse][[/noparse] use String or ]
Serin pin, 16468,[noparse][[/noparse]byte1,byte2- byte8,byte9]
OR
Serin pin, 84,[noparse][[/noparse] use String or ]
Serin pin, 84,[noparse][[/noparse]byte1,byte2- byte8,byte9]
·
And then do a debug out take a look at what shows up
Not knowing what the data is and how much will be showing up will be your major problem

Doug Shave

Thank you for your reply's gentlmen.

I am using the BS2p basic stamp, as far as the device that I am trying to attach to the stamp it is a pulse oximeter.· I am concerned with 3 bytes of data.· The first byte being the status, Second byte the heart rate, and the third byte is the (Oxygen level) Spo2. These 3 bytes are transmitted once per second.

Packet description:

Byte-1······················ Byte-2················· Byte-3

bit7 = 1····················· = 0····················· ·= 0

bit6 = snsd················ =· hr6··················· = sp6

bit5 = oot················· = hr5····················· =sp5

bit4 = lprf················· = hr4······················=sp4

bit3 = mprf··············· = hr3······················ =sp3

bit2 = artf················ = hr2······················ =sp2

bit1 = hr8················ = hr1······················ =sp1

bit0 = hr7················ =hr0························=sp0·



thanks again for the help

Yanroy

it seems to me that the best way to do it would be to have your SERIN read in 5 bytes of data (you're guaranteed to get a complete 3-byte sequence that way) and then look for the byte with the high-bit set and treat that as the start, using that byte and the next two.· This will cause a delay in your program of up to 2 seconds, however.· If you're able to do your other processing in less than a second, you could just do a serin for 3 bytes and if you synchronize it properly when the program first starts, it will stay synchronized.· That method will be trickier.