Barometer delivering wrong measurements when Telemetry connected via Softserial

[int2001]

Not sure if correct here, or at the HW-Vendor.
When connecting HoTT-Telemetry, as described in the Wiki, via a 1N4148 Diode to a SoftSerial-Port (regardless if Serial#1 or Serial#2) the Barometer jumps from 0m to 1000m and Back.

[trollcop]

Unsure,
Unless you're injecting 5V into VDD_IO, which (i've seen it) fucks up the sensor.
I don't know enough about Hott-telemetry to comment about the rest.

[int2001]

Means? Seems to be a HW-Issue. Do i need to "level-shift" the HoTT-Thingy?

[trollcop]

I have no idea what voltages HoTT stuff runs at, but if you're sending >
3.3V to a GPIO pin on STM32, it's bad news.

So yes, I guess a "hardware issue".
But not related to my hardware.

On Sun, Aug 31, 2014 at 12:05 AM, Joerg [email protected] wrote:

Means? Seems to be a HW-Issue. Do i need to "level-shift" the HoTT-Thingy?

—
Reply to this email directly or view it on GitHub
#159 (comment).

[int2001]

I'll do a little bit measurement on the HoTT-Stuff and give you Feedback. Thanks. Please leave issue open, until resolved. Perhaps the Wiki-Entry has to be adjusted after taking the measurements.

[int2001]

According to my measurements the Telemetry-Port of the Graupner GR-16 HoTT is low-Active. In idle (LOW) there are 2V to GND. On HIGH the PIN is shortened to GND

One more thing: If not caring about Baro, everything (HoTT-Telemetry) works fine. But when using Baro for AH, it's a mess.

Any Ideas?

[trollcop]

No, not really.
I did a test before, by making sensor VDD below VCC_IO (by replacing sensor
regulator with 2.5V version) and I observed the behaviour you're describig
(baro sensor crapping out with wrong readings).

On Sun, Aug 31, 2014 at 12:34 AM, Joerg [email protected] wrote:

According to my measurements the Telemetry-Port of the Graupner GR-16 HoTT
is low-Active. In idle (LOW) there are 2V to GND. On HIGH the PIN is
shortened to GND

One more thing: If not caring about Baro, everything (HoTT-Telemetry)
works fine. But when using Baro for AH, it's a mess.

Any Ideas?

—
Reply to this email directly or view it on GitHub
#159 (comment).

[int2001]

OK. however, at least we're talking 'bout the same thing. Really don't know if HW or SW...
If i can help somehow, let me know.

[fiendie]

Is this still relevant?