Hello everyone,
I’m having problems with communicating the board.
I tried to connect it with Arduino mega (connected TX, RX, Vcc, GND, IOREF), I was trying to power it via button.
I tried SerialPassThrough example and even tried to send AT commands directly. The board won’t respond.
Then I tried to measure everything I can with multimeter and noticed that both TXB0104 and TCA9406DCU chips are not receiving 1.8V as well as there is no voltage on C4. It seems that SARA-R4 is either not producing this 1.8V or it is not receiving power at all.
Or maybe there is something that I am doing wrong.
I already tested this on two boards.
By default the SARA-R4 module is turned off, to turn it on – as you might any other cell phone – you need to hold the POWER button down for about 3 seconds.
Run through the guide https://learn.sparkfun.com/tutorials/lt … 1653495744 and see if the SoftwareSerial ones work
Hey @TS-Russell, thanks for your reply.
I got myself and arduino uno and mounted sara board as a shield and it started working. Then I connected sara to mega with wires and it worked as well. So I guess the problem previously was power_on pin as I was trying to power the board with build in “Power” button. I guess the power sequence is not as simple as it seems :).
Anyway, now I have different issue which is sara board powering down by itself after less than a minute after powering up. Now I’m wondering if USB supplies enough current? Had similar problem with a different gsm module. Can anyone confirm/deny that USB current is sufficient for mega/uno+sara combination? I will try to power the whole circuit with an external power supply in any case.