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WiFi chip for Compute Module 3

Sun May 14, 2017 6:07 am

I'm thinking about using a CM3 in a project, but it needs WiFi. Apparently, the RPi 3B has a BCM43143 WiFi chip, but this doesn't appear to be readily available in modest quantities. And it is probably overkill, since I don't need an FM receiver, and I probably won't need Bluetooth. So what's the easiest WiFi chip with an SDIO interface that will work with a minimum of bother with the CM3? I'll probably be using Yocto to build a custom Linux, although any chip that works with Raspbian should be okay.

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Re: WiFi chip for Compute Module 3

Mon May 22, 2017 7:24 pm

I can tell you one to avoid (at least for now). I've been trying to get an ATWILC1000 module working, but the driver support isn't there yet. There's a wilc1000 driver in drivers/staging but I wasn't able to get it to work (though it's being actively updated in the staging-next git repo). There's also an out-of-tree version published by Atmel but it doesn't build in 4.4 or 4.9.

I'll probably kick that one to the curb and look for something else.

One possibility is a USB based Wifi adapter. Since I plan on having a USB hub chip on my carrier board anyway I'll add a type-A jack and plug in one of the off-the-shelf tiny USB Wifi dongles.

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Re: WiFi chip for Compute Module 3

Wed Oct 18, 2017 8:24 pm


Has anyone had any success finding a good option for this? Maybe something that also includes Bluetooth 4.0 (combo chip)

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Re: WiFi chip for Compute Module 3

Wed Nov 15, 2017 3:07 pm

Make it Bluetooth 5 LE + Wi-Fi with QCA4020 from Qualcomm.

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Re: WiFi chip for Compute Module 3

Tue Nov 21, 2017 8:15 pm

Here's some good news for you I ended up looking into this for my own project and I came across the ESP-WROOM-32.

I've managed to fabricate the package/footprint part on Eagle if you're using eagle then I'll happily supply it for you to use.

Below is the schematic I did for mine.
You can power it using 3.3V or via a 5V to 3.3V convertor which is the design on the right hand side.
Connect CTS to GPIO39 & RTS to GPIO38 these are your data flow control pins should you wish to tell the device that you'd like to send/receive data from the pi/esp32
Connect RXD0 to GPIO15 & TXD0 to GPIO14 this is your UART Serial which connects directly into the CM3 as there is no need for a UART to USB Convertor atleast for my project I didn't need to use it and it simplifies the build down alot. However you're welcome to use one. The chip that is used for converting to USB is CP2102-QFN-P28. I've also made a footprint/package for this on eagle as well.

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Re: WiFi chip for Compute Module 3

Fri Dec 15, 2017 10:47 am

I've had good experiences with TI WiLink chips, connected via SDIO. They exist in the form of pre-certified modules from a number of vendors (I used a Jorjin WG7831DELF). WiLink8 chips will do WiFi and Bluetooth, in various bands, depending on the specific option you choose.

TI supplies Linux drivers, which work.
Founder at PartsBox: https://partsbox.io/ (keep track of your electronic components)

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Re: WiFi chip for Compute Module 3

Fri Mar 02, 2018 4:32 pm

Hi jrychter,

The module you suggested sounds like what I'm looking for but I'm struggling to find the drivers. Can you point me at them? Thanks!

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Re: WiFi chip for Compute Module 3

Mon Apr 23, 2018 9:16 pm

Does anyone know the interfaces (port pins) on the Pi 3B BCM2837 SoC for the Wifi/BT chip CYW43438 (was BCM43438)?

The part is CYW43438 (now Cypress) datasheet http://www.cypress.com/file/298076/download
and part is available from US distributors Arrow, DigiKey and Mouser.

So can this be wired to the CM3 to match the Pi3B? Is there a reference design/schematic?
I understand that this would require US FCC Part 15 certification for the RF transmitter.
Last edited by mkirk on Fri Apr 27, 2018 7:25 pm, edited 1 time in total.

John Westlake
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Re: WiFi chip for Compute Module 3

Thu Apr 26, 2018 8:53 pm

I understand it uses a UART channel (for BT) and the secondary SDIO Card interface

I believe these are the I/O pins related to the WiFi / BT on the RPi3

pin@p14 { function = "uart0"; termination = "no_pulling"; drive_strength_mA = < 8 >; }; // TX uart0
pin@p15 { function = "uart0"; termination = "pull_up"; drive_strength_mA = < 8 >; }; // RX uart0
pin@p34 { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
pin@p35 { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
pin@p36 { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
pin@p37 { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
pin@p38 { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
pin@p39 { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
pin@p43 { function = "gp_clk"; termination = "pull_down"; }; // WIFI_CLK - Wifi 32kHz output

I have no direct experience - but this seems an educated guess - atleast a place to start.


Out of interest I've just probed a RPi3 PCB I have here and can confirm the above + an undocumented BT PCM Audio interface to the SoC

https://www.dropbox.com/s/bvxiws83xvy3t ... s.JPG?dl=0

I've highlighted the relent connections + note the x4 extra BT PCM audiopath connections (not required for WiFi / BT).

There might be secondary connections such as Reset / PowerDown... I cannot be sure, but these are the main SoC interface connections.

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Re: WiFi chip for Compute Module 3

Fri Apr 27, 2018 8:59 am

We discussed this also here Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
GPIO 32-33 UART0 for BT
GPIO 34-38 SD1 for Wifi
GPIO 42 GPCLK1 for Ethernet 25MHz output
GPIO 43 GPCLK2 for Wifi 32kHz output

Port Expander

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Re: WiFi chip for Compute Module 3

Fri Apr 27, 2018 4:34 pm

Thanks to all for the great information!

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