UART HARDWARE Uc - EC21 and Quectel_UMTS & LTE_EVB KIT

Technical Subjects Hardware Baseband
1

Hi, I have Quectel_UMTS & LTE_EVB KIT, and I want to connect with a MCU PIC18 (3v3 supply),
In the following image you can see that there are some interfaces that pass the voltages from 1.8 to 3.0 v:

quecte
quecte792×1928 403 KB

Looking at these diagrams, I distrusted the 3.0 V of the quectel manual, and measured the Vccb pin (19) from U403 Ic, and it is at 3.21 V, I don’t really know if it is at 3.0 or 3.3v.

Does anyone know if there is any test pin where I can go by TTL to the UART of my IC at 3.3V level supply? Tanks.

2

Hi,
1- what really you need, do you want to use 3.3V from EVB.
OR
2- you want to use MAIN or DEBUG UART from module side?

if you want test point just for voltage.
image
in image you can see J804 pin number 1 is the voltage pin. i also measure the voltage is 3.21 at this pin.

3

Yes, I can see that, I measure 3.21, my question is I can use UART 3.0 V with my microcontroller UART at 3.3 V? I dont want to use de debug port…
Thanks

4

yes you can use the UART with you 3.3V microcontroller.