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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

[email protected] { function = "uart0"; termination = "no_pulling"; drive_strength_mA = < 8 >; }; // TX uart0
[email protected] { function = "uart0"; termination = "pull_up"; drive_strength_mA = < 8 >; }; // RX uart0
[email protected] { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
[email protected] { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
[email protected] { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
[email protected] { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
[email protected] { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
[email protected] { function = "input"; termination = "pull_up"; drive_strength_mA = < 8 >; };
[email protected] { 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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Location: Denver, CO, USA

Re: WiFi chip for Compute Module 3

Sat Oct 13, 2018 12:43 am

I read this thread and after much further research, I decided to use a Ti WiLink8 chipset. The Jorjin WG7831DELF module is no longer available for purchase in the USA, so I looked on Ti's website, and found a few other similar modules. I decided to use a Laird LSR TiWi-BLE module, part number 450-0064R (I get them on Tape and reel), it is a Ti WiLink 8 SiP on a board with gold fingers and a U.FL connector for the antenna. It has full FCC certification, and should not require additional FCC testing if paired with one of two antennas sold by Laird (part numbers 001-0010 for a 2dB IP67 waterproof 50Ω impedance antenna and 001-0001 for a non-waterproof 2dB 50Ω impedance antenna). I can say that the Ti WiLink8 Kernel module can cross-compile for ARMv8 with Raspbian Kernel v.4.14.71. You need to supply a 32.768kHz clock signal, and all IO and power needs to be 1.8V except for VBAT. I am using a Ti TXB0108PWR voltage level translator to downshift the 3.3V IO to 1.8V, the other option is to supply 1.8V to one of the GPIO VREF's and run IO at 1.8V. WLAN interfaces over SDIO on SD1. BLE interfaces over UART. There is an RS232 interface for WLAN debugging which should be broken out to headers. The symbol, footprint and 3D model can be downloaded from UltraLibrarian for any ECAD software: https://app.ultralibrarian.com/Details/ ... 7111&tab=m. For getting started on building the Ti WiLink8 Kernel module, take a look at this wiki: http://processors.wiki.ti.com/index.php ... e_Linux.29

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