PKE8721DAF

Tags: chip:rtl8721dx arch:arm vendor:realtek

The PKE8721DAF is a Realtek RTL8721Dx development board built around the RTL8721DAF (QFN48, 4 MB NOR flash). NuttX runs on the KM4 application core — an Arm Cortex-M55-compatible core running at up to 345 MHz. See the RTL8721Dx chip documentation for the full SoC specifications and the vendor-SDK dependency.

Features

RTL8721DAF: Arm Cortex-M55-compatible KM4 core up to 345 MHz, 512 KB SRAM, 4 MB NOR flash
Wi-Fi 4 dual-band (2.4 / 5 GHz) station and SoftAP
SPI NOR flash (XIP)
LOG-UART console

Supported in this NuttX port:

NSH shell over the LOG-UART console
littlefs persistent storage mounted at /data (a dedicated SPI NOR flash partition), backing the Wi-Fi key-value store
Wi-Fi station and SoftAP through the wapi tool
DHCP client (STA) and DHCP server (SoftAP)
GPIO pins exposed as /dev/gpioN character devices (input, output and interrupt), driven directly on the SDK fwlib register layer
General-purpose UARTs exposed as /dev/ttySN serial devices, driven directly on the SDK fwlib register layer

Buttons and LEDs

This NuttX port does not wire any user buttons or LEDs.

Configurations

Build and flash any of these per the RTL8721Dx build instructions; for the CMake build, source . tools/ameba/env.sh pke8721daf first (the make build needs no sourcing).

$ ./tools/configure.sh pke8721daf:<config-name>

nsh

Networking-enabled NSH with littlefs at /data and the wapi Wi-Fi tool. The console is the LOG-UART at 1500000 8N1 (the rate is configured by the bootloader and inherited by NuttX). The Wi-Fi examples below are available from this configuration.

gpio

Minimal NSH with the GPIO driver and the gpio example enabled (no Wi-Fi). The board registers three pins from its pin table (see boards/arm/rtl8721dx/pke8721daf/src/rtl8721dx_gpio.c): an output at /dev/gpio0, an input at /dev/gpio1 and an interrupt pin at /dev/gpio2. Edit that table to match a board’s wiring. Exercise them with the example:

nsh> gpio -o 1 /dev/gpio0     # drive the output high
nsh> gpio /dev/gpio1          # read the input
nsh> gpio -w 1 /dev/gpio2     # wait for a falling-edge interrupt

Pins are encoded with the AMEBA_PA() / AMEBA_PB() helpers from arch/arm/src/common/ameba/ameba_gpio.h (port A/B, pin 0-31), matching the Ameba SDK PinName layout.

uart

Minimal NSH with the general-purpose UART driver and the serialrx / serialblaster examples enabled (no Wi-Fi). The LOG-UART owns the console and /dev/ttyS0, so the board registers UART0 from its table (see boards/arm/rtl8721dx/pke8721daf/src/rtl8721dx_uart.c) as /dev/ttyS1 at 115200 8N1. Edit that table – controller, TX/RX pads and baud – to match a board’s wiring. The TX/RX pads use the same AMEBA_PA() / AMEBA_PB() encoding as the GPIO table; the driver muxes them to the UART function and pulls RX high through the SDK ROM. Exercise the port with the examples (loop TX back to RX, or wire it to a host serial adapter):

nsh> serialblaster    # stream a test pattern out /dev/ttyS1
nsh> serialrx         # receive and dump bytes from /dev/ttyS1

The line format can be changed at runtime through tcsetattr() (the config enables CONFIG_SERIAL_TERMIOS). UART2 is shared with Bluetooth and is not exposed by the driver.

Wi-Fi

Station (connect to an AP):

nsh> wapi psk    wlan0 <password> 3
nsh> wapi essid  wlan0 <ssid> 1
nsh> renew wlan0

SoftAP (become an access point, with a DHCP server for clients):

nsh> wapi mode   wlan0 3
nsh> wapi psk    wlan0 <password> 3
nsh> wapi essid  wlan0 <ssid> 1
nsh> ifconfig    wlan0 192.168.4.1 netmask 255.255.255.0
nsh> dhcpd_start wlan0

Stop the SoftAP with wapi essid wlan0 <ssid> 0.

License Exceptions

This board depends on Realtek vendor code that is not part of NuttX and is subject to its own license:

The prebuilt Wi-Fi / Bluetooth firmware image and the Realtek ameba-rtos SDK libraries/headers linked into the image. See the SDK’s own license; the SDK is auto-fetched and is not redistributed in the NuttX tree.