The QN908x CPU has several timer modules: one RTC (Real-Time Clock) that
can count from the 32kHz internal clock or 32.768 kHz external clock,
four CTIMER that use the APB clock and have four channels each and one
SCT timer with up to 10 channels running on the AHB clock.
This patch implements a timer driver for the CTIMER blocks only, which
is enough to make the xtimer module work. Future patches should improve
on this module to support using the RTC CNT2 32-bit free-running
counter unit and/or the SCT timer.
The QN908x has four FLEXCOMM interfaces that support a subset of UART,
SPI or I2C each one. This patch adds generic support for dealing with
the FLEXCOMM initialization and interrupts and adds a driver for
RX/TX support in UART.
With this patch is now possible to use a shell on the device over UART.
The QN9080DK is the developer board reference from NXP for the QN908x
CPUs. The developer kit comes with two boards: a larger PCB with many
peripherals and a much smaller "USB dongle". This board adds initial
support for the larger "DK board". At the moment, with the minimal CPU
support this board only configures the GPIOs available in the board,
namely the RGB LED and the two user buttons.
