Port, board and/or hardware

RPI_PICO_2_W

MicroPython version

MicroPython v1.25.0-preview.307.g4364d9411 on 2025-02-23; Raspberry Pi Pico 2 W with RP2350

Reproduction

Save the following code onto the Pico 2 W and run it with either CPU_FREQ = 300_000_000 or CPU_FREQ = 150_000_000 uncommented.

When using the overclocked frequency, the following error is printed and the access point is not available to connect to: [CYW43] Failed to start CYW43

When using the default frequency the access point can be connected to and no errors are printed

import machine
import network
"""
When overclocked we get

[CYW43] Failed to start CYW43

When using default CPU frequency
the wifi starts fine
"""
CPU_FREQ = 300_000_000  # overclocked
#CPU_FREQ = 150_000_000  # default

machine.freq(CPU_FREQ)

wifi = network.WLAN(network.WLAN.IF_AP)
wifi.config(
    ssid="pico2w_ap",
    channel=10,
    security=network.WLAN.SEC_OPEN,
)
wifi.active(True)

Expected behaviour

WiFi should work if the CPU is overclocked

Observed behaviour

When the CPU is overclocked, the wireless card firmware does not appear to initialize correctly:

[CYW43] Failed to start CYW43

Additional Information

My testing setup has 2 I2C devices connected: an OLED display GP0 & GP1 and a battery-backed realtime clock on GP2 & GP3. The code above does not initialize these devices, so I don't think their presence should have any impact; it looks like simply changing the CPU frequency is enough.

Doing a little trial-and-error changing the frequencies in the script above it looks like 270MHz is the upper limit of what the wifi can handle. Is this a known limitation of the firmware?

Code of Conduct

Yes, I agree