Using an SiP chip.

Thread Starter

Njolac

Joined Mar 29, 2022
3
Hello everyone,
i am currently designing a PCB for a school project and have some difficulties in it's implementation. I want to use an STM32 MCU and make a PCB for it, the MCU does not contain any wireless communication capability, so I need to add a WLAN module to it. I have chosen this chip: WFM200SS22XNN2, since it is the cheapest for now. How does one connect and program this? Do SiP chips even need programming? I planned on using USART for getting data from the STM to the module (RF_1 and RF_2 are Tx/Rx pins), and am wondering if this is the right approach or is there something simpler/better? Is there a better alternative to this module (I need something that can be soldered on the PCB)?

Any help would be appreciated. Thank you in advance.
 

Ya’akov

Joined Jan 27, 2019
6,856
Welcome to AAC.

Did you read the design guide? If you can't understand the requirements from it the complexity of layout and configuration for this device seems more than you can manage. It requites both very careful layout due to RF considerations and special configuration files and firmware not even covered in the guide, just referred to.

Before anyone could recommend a solution they need to understand the problem.

What are you going to be using the WiFi to do?
What kind of data rates will this require?
How much space do you have on your board?
How many boards to you plan to produce?
Will you be selling this board?
 

Thread Starter

Njolac

Joined Mar 29, 2022
3
Thank you for a quick reply. The job of the board will be to acquire data from a soil moisture sensor, and send them through wifi to a server (most likely on a laptop). The only thing required for this, is for it to work (accuracy and speed are not really what's important for the project). I reckon that the data rates won't be very high. The space on the board is not really an issue, because this is a school project, and only one board will be produced, which will not be sold.
As for the guide, I had a rough idea of how to connect it with the STM32, but not an idea on how to actually program it to send data.
Thank you again for the reply and for any further help.
 

Ya’akov

Joined Jan 27, 2019
6,856
Thank you for a quick reply. The job of the board will be to acquire data from a soil moisture sensor, and send them through wifi to a server (most likely on a laptop). The only thing required for this, is for it to work (accuracy and speed are not really what's important for the project). I reckon that the data rates won't be very high. The space on the board is not really an issue, because this is a school project, and only one board will be produced, which will not be sold.
As for the guide, I had a rough idea of how to connect it with the STM32, but not an idea on how to actually program it to send data.
Thank you again for the reply and for any further help.
OK then I have a simple suggestion. An ESP-M3 module which uses the ESP8285. There are two versions of the firmware, one uses an AT command set, that’s the one you want. The module is very easy to use and very small. It is on a PCB but it has castellated holes at the edge for soldering.

1648548985309.png
They are can be very cheap (~$1.25) but you would have to wait for shipping. There are other sources, including Mouser who stocks the Adafruit version.

This would allow you to simply solder it in place and use WiFi as if it was serial. The “transparent” version of the firmware might be attractive now that I think about it. In that version the MCU doesn’t do anything except communicate via UART and the configuration of the module is via self-hosted web page. I haven’t used that version but it’s worth a look.
 

Thread Starter

Njolac

Joined Mar 29, 2022
3
After searching for a bit, I wasn't able to find a seller that currently supplies this chip. I have, however, found a cheap alternative in the ESP-C3, do you think it would be a good alternative or is the chip you reccomended a must?
 

BobTPH

Joined Jun 5, 2013
6,080
Stop looking at chips. You are much better off with a board solution like Yaakov recommended. I use the ESP-01 module myself. These are available everywhere, cheap, easy to use, and plug in to a 4x8 header.

ESP-01

Bob
 

Ya’akov

Joined Jan 27, 2019
6,856
After searching for a bit, I wasn't able to find a seller that currently supplies this chip. I have, however, found a cheap alternative in the ESP-C3, do you think it would be a good alternative or is the chip you reccomended a must?
I gave you two links to what I was talking about which report having stock. The board I referred to has all of the heavy lifting done and can be soldered directly to your board which is common practice.
 

Ya’akov

Joined Jan 27, 2019
6,856
Stop looking at chips. You are much better off with a board solution like Yaakov recommended. I use the ESP-01 module myself. These are available everywhere, cheap, easy to use, and plug in to a 4x8 header.

ESP-01

Bob
Take a look at the ESP-M3, Bob. It's 8266 compatible, tiny and designed for this job. But it can be used as a very small WiFi enabled MCU. Pretty neat.
 
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