openrcforums

After some experiments where I successfully got a PIC micro-controller talking S.Port, I finally got round to designing and ordering prototype boards for my S.Port variometer+ project. It has a Freescale MPL3115A2 pressure sensor module fitted that's supposed to be able to read down to a 10 cm altit...

OK, I eventually got round to doing the tests; I was not getting 7E-1B data out of the back of the Taranis (but I was getting 7E-98 data). After much reading, I realized that you only get S.Port data down-linked to the Taranis when you're in D16 mode , I was in D8 mode because the receiver instructi...

Mike,

I won't be able to check that data arrives at the TX for a couple of days but thanks for the suggestion.

Am I right in saying that I must have the latest software build on these boards because my analog sensor boards give the second output after I've shorted pin 2 to ground?

Thanks,

Hmmm,

Maybe my receiver needs a software upgrade? Any ideas?

Q1. I can't get any data that I see on the scope/protocol analyzer to appear in the telemetry screens, I added A2 and set FSD to 13.8v in model setup but A2 reads zero all the time. What tx firmware and revision are you using? I'm using a new Taranis with opentx-r2940, Date 2014-02-02, Time 17:08:5...

Sorry if people were reading mixed up captions, I was fighting with the upload captions to get them right.

Mike,

You're right, the waveform IS inverted, I had a brain fart because I saw 0v that ramps up to 3v for the signal but the 3v level represents a '0' so idle low = idle at '1'. Here are some waveforms...

More observations Still reading through the main RCGroups thread. I tried looking at the T2 parameter (I am looking at A1,A2,T1,T2, and Batt) and I do see the data passed from the 2nd analog in (ATTiny pin 2) passed through to T2 but I get nothing at all on A2 or T1. A1 gives me the receiver batter...

OK, what I've discovered so far: The serial data on S.Port uses positive inverted logic levels, i.e 3.3v = 0 and ov = 1. i.e. 3.3v = 1 and 0v = 0 (someone told me that it was inverted - it isn't) The X8R sends out 7E.XX aprox every 11 mS where XX is a single byte device number The X8R polls multiple...

If anyone's interested, here's my schematic. Not sure which pad is the "2nd analog input" though. I guess I can look at the code and the data sheet.

OK, thanks. Mine have yellow stickers on them which I suspect is the marker but there's nothing written on the sticker. I'll do the test you suggest when I run them up this weekend. I've borrowed a Tektronix scope that has a serial protocol analyzer so I'll be able to decode the data passing over th...

Mike,

Will the boards I have have just received be loaded with the latest firmware or should I update them?

Well I think I figured it out, the extra 2 connections at the lower right are called bypass which allows you to connect the other side of the 15k input resistor. I have some code running on a PIC16F1823 that sends out 57,600 baud serial in the right format, I will try to get it running against the 8...

Mike,

The boards arrived yesterday, they are not the same as the picture that's on Aloft's web site, it seems that the potential divider resistors have been turned into 0603 (or 0402?) SMT parts; do you have updated instructions or should I chase this down with Aloft?

Thanks in advance.

Thanks for all the input guys, I've ordered a couple of Mike's boards from Aloft Hobbies to check them out.

Mike, I didn't realize you were the one that wrote the code for this - I am humbled! Can you share any more information about the bus timing? If this runs on +, _, and Sdata then there is no Sclk line so it can't be SPI or I2C? If not then I guess that the timing is important both ends? If serial da...

Your link didn't show me any pictures but the one I was thinking of is here http://www.alofthobbies.com/x8r2analog.html Is that the same thing? I should buy one of these and check it out. It seems to me that the ATTiny should be capable of S.Port; clearly they used the ATTiny and maybe a circuit lik...

Thanks Mike, I was aware that SPort and SBus are different. I saw a small board somewhere that connected to SPort that used an ATTiny processor, I'm looking at the datasheet for that right now. [Edit] Looks like the ATTiny 2313 can handle inverted serial either in the USART or the USI interface, I'm...

Thanks for all the replies, especially the link from mstrens which I had not found. I only need 2 bytes (or 16-bit words) of data from a plane-mounted detector, one will be an ID and the other a signal level. It seems that the S.Port on the receiver is just polling through all the various IDs so the...

Can anyone provide any information (or links) on the S.Port protocol? I am an embedded systems engineer and I want to make a device that communicates via the S.Port with the basic idea of getting data from the plane back to the transmitter. FrSky seem to have been saying that they were going to rele...