nuttx/Documentation/platforms/arm/rtl8721dx
dechao_gong 2cc38e43fb arch/arm/rtl8721dx: add shared Ameba timer driver
Add a parameterised NuttX timer lower-half for the Realtek Ameba
general-purpose timers, sitting on the SDK fwlib RTIM register layer and
registered at /dev/timerN.  The shared driver
(arch/arm/src/common/ameba/ameba_timer.c) reads a per-chip instance
table (ameba_timer_chip.h) for each timer's base, input clock, RCC gate
masks and IRQ; the period is programmed directly in microseconds and
converted to the 32-bit auto-reload with one clkfreq formula.

On the pke8721daf two of the 32.768 kHz "basic" (LTIM) timers are
exposed: /dev/timer0 is TIM1 and /dev/timer1 is TIM2.  TIM0 is left
untouched because the boot ROM claims it as the always-on system timer
(SYSTIMER); reprogramming it would break every SDK delay.  The RTIM
time-base entry points resolve to ROM, while the interrupt-clear and
period-change helpers come from the fwlib RAM source ameba_tim.c (shared
with the PWM driver).

Verified on hardware with examples/timer against both devices: the
update interrupt fires at the requested 1 s interval (measured with the
independent ROM SYSTIMER = 32768 ticks = 1.000 s).

Also whitelist the vendor RTIM_ symbol prefix in tools/nxstyle.c,
alongside the existing RCC_/SYSTIMER_ Ameba SDK entries.

Assisted-by: Claude <noreply@anthropic.com>
Signed-off-by: dechao_gong <dechao_gong@realsil.com.cn>
2026-09-01 17:41:14 +08:00
..
boards/pke8721daf arch/arm/rtl8721dx: add shared Ameba timer driver 2026-09-01 17:41:14 +08:00
index.rst arch/arm/ameba: add CMake build support for RTL8721Dx and RTL8720F 2026-07-17 08:30:47 -03:00