Chinese SIM7600E breakout board

Projects Networking, Protocols, and Devices
1

Hello :). Stupid question again
Have anyone had any experience with this board?

image
image800×800 54.1 KB

I was trying to find any schematics/datasheet but so far only found that board is of "RushPro" chinese brand

What voltage their UART pins are at? Some of 7600 boards state 1.8, some 3.3. Some say it is configurable via some magic pins up to 5v.

How one can check the Rx/Tx voltage without an oscilloscope? Picture above defenitely has some sort of level converter (transistors+resistors)

Youtube suggests that it is OK to connect it straight to ESP32 but I am in doubt

Board also has VBAT pin which is 3.7v pin (one have to use either V pin feeding 5v OR VBAT pin at 3.7, not both).

2

If I remember correctly, it's the SIM card slot which supports 1.8V and 3V SIM cards.

1 Like
3

The datasheet states the module operates between 3.4V and 4.2V and you can find more information about the UART in the SIM7100 SIM7500 SIM7600 Series UART Application Note (V2.00)

image
image1274×967 105 KB

Your module shows a USB interface and on aliexpress you can see some screenshots of the Serial test with AT commands

image
image1154×1088 154 KB

image
image1137×987 94.7 KB

image
image1149×1121 101 KB

➜ have you tried just connecting through USB and see if there is an associated virtual COM port where you could use a terminal application to send AT commands ? if you have a scope you could also monitor what's going on on the Tx and Rx pins

additionally found this board (not yours)

where they state

Hardware Interface
SIM Card Slot Both are supported, compatible with 1.8V and 3V SIM cards
UART Interface Both are supported, the serial port sends and receives AT commands, and is compatible with 3.3V/5V working level

but this is a probably a feature of that specific board, may be yours is the same...

4

Well if it says "default status: pull-up" for Rx and Tx then I can just powerup this board alone and simply check the voltage on these pins? Must be either 1.8 or 3.3. Lets see.

5

right

6

Here are some specs. But in Chinese: https://de.aliexpress.com/item/4000591184815.html?gatewayAdapt=glo2deu

7

For those interested: UART on this module is 3.3v. Vcc is 5v. Module can be interfaced directly to an ESP32

8

Thanks for providing the answer

9

Oh. Was celebrating too early :(.

Just found that voltage on SIM7600 TX pin is 4.3v, while RX pin is at 3.3.

Connected this SIM7600 board to my laptop via USB and it works just fine. Responds to AT commands etc.

Can't get it working with ESP32 UART. SIM800 board works and responds to commands being attached to the same ESP32 board at the same pins.

Any ideas? Bad SIM7600?

It is definitely not a ESP32 problem as it works with SIM800 module attached to the same pins.

10

Any recommendations where tto buy 100% working SIM7600 module?

11

This SIM7600E module has an USB port. Could it be converted to UART with some extra adapters? It is not an USB host so I am not sure if all those "USB to TTL" converters can be used

12

Oh nevermind.

  1. Board has its pins mislabelled:
    "T" on the SIM7600 module should be connected to MCU's UART TX and "R" to the MCU's UART_RX.

  2. Must be powered from a separate high-current power supply. Powering from ESP32 DevKit's 5v pin leads to unstable operation (resets)

Finally.

13

glad you solved it

1 Like
14

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.