I recently had my onboard SPI receiver go in my Eachine UZ65. I was looking at the spec sheet for the receiver and the operating voltage is 3.5V-10V. Before I take the time to squeak this little guy in is it going to drop out of the sky and failsafe when my battery hits 3.4? Anyone use one of these down to 3.1V?

I use XM receiver on my Mobula6HD and I haven't had any failsafe when the voltage dropped to low 3s Volt which is quite easy to do with the Mob6.

There is a 5V regulator on the FC. Even if the voltage is lower, the voltage is step up to 5v. So your receiver will still work as long as there is energy. But below 3V, your lipo will pretty much die off.

Thanks for the input! 

Just incase somebody stumbles across this at some point, that flight controller does not support external FrSky receivers. There goes about 4 hours....

(02-Oct-2020, 11:56 PM)Swifty Wrote: Just incase somebody stumbles across this at some point, that flight controller does not support external FrSky receivers. There goes about 4 hours....

Any flight controller that has a spare UART will support an external FrSky receiver. The Superbee F4 flight controller used on the Eachine UZ65 has two UARTs, and UART1 even has an inverted for pad (IR1) for an SBUS connection.

Why couldn't you get it working?

When I was trouble shooting receivers not working in BF I came across a video where they said make sure your FC supports your receiver. My manual says it supports external DSM2/DSMX and TBS crossfire. The BangGood website lists firmware targets for Frsky SPI, DSM2/DSMX, and TBS Crossfire receivers. I didn't see anything for SBUS, assumed that was my issue.

I soldered the receivers SBUS to the RX2 pad. Do I just solder to IR1 and run the FrSky SPI firmware?

As Snow pointed out, use the IR1 for Frsky XM receiver and turn on serial RX on UART 1 on the BF Port tap and then choose SBUS on configuration receiver setting.

SPI is for built in receiver, the exact thing you are trying to avoid/fix by adding an external receiver here.

(03-Oct-2020, 01:15 AM)Swifty Wrote: When I was trouble shooting receivers not working in BF I came across a video where they said make sure your FC supports your receiver. My manual says it supports external DSM2/DSMX and TBS crossfire. The BangGood website lists firmware targets for Frsky SPI, DSM2/DSMX, and TBS Crossfire receivers. I didn't see anything for SBUS, assumed that was my issue.

I soldered the receivers SBUS to the RX2 pad. Do I just solder to IR1 and run the FrSky SPI firmware?

With an external receiver connected and the receiver protocol changed to SBUS, doing that will switch off / disable the internal SPI receiver so you are then running using the external XM receiver.

The only reason the documentation doesn't mention an external FrSky receiver is because they assume you will be using the built in SPI FrSky one. Betaflight supports all the common protocols including the FrSky ones (ACCST D16 in the case of the XM) and the board has common UARTs so it supports anf UART device that Betaflight has support for.

Once you've moves the SBUS connection ti the IR1 pad, set UART1 to be for "Serial RX" in the Ports tab, and set the serial receiver provider to be SBUS in the Configuration tab it should just work. Obviously you will need to bind your transmitter to the XM receiver too.

i would go for the r-xsr receiver as it is small like the xm, but has a better range. sure the size of the xmplus wont be a true issue...

(03-Oct-2020, 09:34 AM)SnowLeopardFPV Wrote: With an external receiver connected and the receiver protocol changed to SBUS, doing that will switch off / disable the internal SPI receiver so you are then running using the external XM receiver.

The only reason the documentation doesn't mention an external FrSky receiver is because they assume you will be using the built in SPI FrSky one. Betaflight supports all the common protocols including the FrSky ones (ACCST D16 in the case of the XM) and the board has common UARTs so it supports anf UART device that Betaflight has support for.

Once you've moves the SBUS connection ti the IR1 pad, set UART1 to be for "Serial RX" in the Ports tab, and set the serial receiver provider to be SBUS in the Configuration tab it should just work. Obviously you will need to bind your transmitter to the XM receiver too.

Thanks for the detailed explanation, managed to get it working after switching it to IR1. Thank you very much!