Add WLAN mPCIe Card AW7915-NPD on OpenWRT Version 24.10

Hardware Questions and Recommendations
1

Hello,
i'm trying to install the following WLAN card "AW7915-NPD" on my APU1D board in OpenWRT. After booting, I get the following error message: "See file as Attachment"

Boot Process APU1D
Boot Process APU1D1920×1440 327 KB

After that, OpenWRT crashes. I've installed the following kernel drivers:
"kmod-mt7915 and kmod-mt7915e"
Kernel Version:

root@rome01:~# uname -a
Linux rome01.intern.example.com 6.6.73 #0 SMP Mon Feb  3 23:09:37 2025 x86_64 GNU/Linux

Why do I get a timeout? What can I do?
Regards, Stefan

2

I could easily imagine the APU1D being seriously under powered for this kind of card ...

3

Okay, which board would you recommend for the card?

4

I would recommend a dedicated router or AP for the wireless.

5

I would like to use the card on my board. Which board would support the card?

6

Even if the board is too small, this has nothing to do with the error message.

7

if the card dies, due to (theoretical) insufficient power, you see no reason for the OS to crash ?

8

The board has the following specifications:

  • 12V DC, about 6 to 12W depending on CPU load. Jack = 2.5 mm, center positive
  • Expansion: 2 miniPCI express (one with SIM socket), LPC bus, GPIO header, I2C bus, COM2 (3.3V RXD / TXD)

The Card has the following specifications:

  • Operating Voltage DC 3.3V ± 5%
  • Power consumption maximum is 9W, average is 4 – 8W. Main board Power Supply design please provide 3.3V 3A, minimum 3.3V 2.5A.

Should fit, right?

9

Very unlikely.

It draws 10 W on the 3.3 V rail alone (and it really does, all the time and more) and it gets very hot while doing so, heatsink required, active cooling recommended.

Chances that the onboard voltage regulators of the APU1D can provide 3.3V 3A, without cooking themselves to death and fluctuating voltage while trying, minimal.
Chances that the external PSU will provide twice the expected power draw (the 10W plus regulator losses of this WLAN card come on top), not all that good.
Chances that the WLAN card will overheat and crash the whole system within seconds, high.
Chances that it will work inside the closed stock APU1D case, zero, core meltdown guaranteed.

1 Like
10

Hello slh, can you recommend a board where I can use the AW7915-NPD card?

11

Hello, can I solve the power problem on my board as described here?

Solution

12

I found the following circuit diagram.
APU1D
Where should I feed the 3.3V?

13

The card was tested on the APU2 board.
https://pcengines.github.io/apu2-documentation/mpcie_modules/

14

I am using the same card, I get the exact same error messages, and I have been hitting my head against the wall whether it has something to do with power delivery. The reason I believe it is not power related is because sometimes it initializes properly and when it is working, it is working very stable, it can run for many days.
The problem happens during initialization.
I have a motherboard with m2 A/E key for wifi cards which I believe should be more than capable of supplying at least 10W of power.
Besides, the card works with any kernel pre 5.15 (with 5.15 being the last where it works).