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Wifi Solution: Wake on WLAN on AFE-R750

Implementation guide for Wake-on-WLAN (WoWLAN) on AFE-R750 with EWM-W179 module.

Use Case​

Application: AFE-R750 as AMR (Automated Mobile Robot) controller

Requirements:

  • Save battery power by suspending AFE-R750 when AMR reaches target position
  • Wake via WoWLAN (Wi-Fi) when AMR needs to move to other position

Background Analysis​

Key Points:

  1. ✅ Wi-Fi module is still alive if AFE-R750 suspends
  2. ✅ Wi-Fi module supports wake-up function
  3. ✅ AFE-R750 hardware has dedicated wake-up pin
  4. ✅ AFE-R750 BSP supports wake-up function

Implementation Steps​

Step 1: Power Verification​

Basic Checking Method: Measure the VDD_3V3_MKE pin voltage.

Result: After AFE-R750 suspends, the VDD_3V3_MKE pin still has 3.3V.

Power Verification

Step 2: Driver Compilation​

EWM-W179 supports wake-on-function, but its driver must be re-compiled with WOWLAN=y.

Set Up Environment:

sudo rm -r /lib/modules/$(uname -r)/build
sudo rm -r /lib/modules/$(uname -r)/source
sudo cp -r /usr/src/linux-headers-5.15.148-tegra-ubuntu22.04_aarch64/3rdparty/canonical/linux-jammy/kernel-source /lib/modules/$(uname -r)/build
sudo ln -s /lib/modules/$(uname -r)/build /lib/modules/$(uname -r)/source
sudo cp -r /lib/modules/$(uname -r)/build/arch/arm64 /lib/modules/$(uname -r)/build/arch/aarch64

Then follow the FAQ to build Wi-Fi driver with wake-on-function.

📥 Download: FAQ to build Wi-Fi driver

Important: Ensure your build environment matches the requirements in the FAQ document before proceeding.

Driver Compilation

Step 3: Test Wake Function​

After installing new driver:

  1. Set AFE-R750 to suspend
  2. Send wake-up packet by MAGPAC utility
  3. Measure M.2 A+E key pin 55 (wake-up pin) by voltage meter

Expected Behavior:

  • When AFE-R750 suspends: Pin 55 is HIGH
  • EWM-W179 receives wake-up packet: Pin 55 becomes LOW

Result: Wake-on-WLAN function is working on Wi-Fi module.

Step 4: Hardware Design Verification​

PCIE_WAKE_N Signal: Check that PCIE_WAKE_N signal and M.2 pin 55 are connected via R464.

PCIE_WAKE_N Connection

GPIO Configuration: PCIE_WAKE_N is connected to SoC PEX_WAKE_N, A8 pin which also is GPIO L,2 pin.

GPIO Pin Assignment

GPIO Configuration

So the last part is BSP supporting wake-on by GPIO L,2.

Step 5: BSP Configuration​

Checking with vendor, WOW function needs to add these items into BSP:

  1. Wake event should include GPIO L,2
  2. GPIO L,2 should be HIGH in default, and active LOW
  3. GPIO L,2 default be occupied by wake-on-WLAN function

Apply Patch:

patch -p0 < wow_jp61_afe-r750.patch

📥 Download: BSP Patch (wow_jp61_afe-r750.patch)

Note: Apply this patch before compiling your BSP to enable complete WoWLAN functionality.

BSP Patch Application

Step 6: Final Setup​

After the patched BSP is compiled and image is flashed into AFE-R750:

  1. Verify: Make sure the probed Wi-Fi driver has enabled WOW function
  2. Enable WOW: 
    sudo iw phy0 wowlan enable any
  3. Test Wake: 
    sudo wakeonlan <MAC with :>

Result: AFE-R750 can be woken if Wi-Fi receives wake-on packet from MAGPAC or wakeonlan command.

References​

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