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boards/arm/ht32f491x3: Add PWM support for the HT32F49163 Starter Kit board #18649

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126 changes: 117 additions & 9 deletions Documentation/platforms/arm/ht32f491x3/boards/esk32/index.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ ESK32 (HT32F49163)
The ESK32 is a development board based on the Holtek HT32F49163 MCU.
The current NuttX port targets the HT32F49163 device used on the
HT32F49163 development kit and focuses on a working serial-console NSH
configuration with basic board bring-up.
configuration with basic board bring-up plus timer-based PWM validation.

For additional hardware details, refer to Holtek's
`HT32F491x3 Starter Kit User Guide <https://www.holtek.com/webapi/106680/HT32F491x3_StarterKitUserManualv100.pdf>`_.
Expand All @@ -28,6 +28,7 @@ The current port provides:
* Boot and clock initialization for the ESK32 8 MHz external crystal
* System clock configured to 150 MHz
* USART1 serial console at 115200 8N1
* TMR3 PWM outputs exposed through ``/dev/pwm0`` .. ``/dev/pwm3``
* ``/bin`` mounted through ``binfs``
* ``/proc`` mounted through ``procfs``
* User LED registration through ``/dev/userleds``
Expand All @@ -41,6 +42,10 @@ applications:
* ``dumpstack``
* ``leds``

The ``esk32:pwm`` configuration keeps the same board bring-up and adds the
``pwm`` example application together with a board-level PWM device at
``/dev/pwm0`` .. ``/dev/pwm3``.

Buttons and LEDs
================

Expand Down Expand Up @@ -75,8 +80,12 @@ The current port uses the following MCU pins:
===== ========== ==========
Pin Signal Notes
===== ========== ==========
PA6 TMR3_CH1 ``/dev/pwm0`` output in ``esk32:pwm``
PA7 TMR3_CH2 ``/dev/pwm1`` output in ``esk32:pwm``
PA9 USART1_TX Default serial console TX
PA10 USART1_RX Default serial console RX
PB0 TMR3_CH3 ``/dev/pwm2`` output in ``esk32:pwm``
PB1 TMR3_CH4 ``/dev/pwm3`` output in ``esk32:pwm``
PD13 LED2 User LED, active-low
PD14 LED3 User LED, active-low
PD15 LED4 User LED, active-low
Expand Down Expand Up @@ -124,16 +133,72 @@ The following commands are useful for validating the current port:
When ``leds`` is executed, the example opens ``/dev/userleds`` and cycles
through the LED bitmasks supported by the board.

Current Limitations
===================
The ``esk32:pwm`` configuration also exposes ``/dev/pwm0`` through TMR3. The
default defconfig selects ``CONFIG_HT32F491X3_TMR3_CHANNEL=1``, so the PWM
signal is routed to ``PA6``. Probe ``PA6`` against board ``GND`` and run:

.. code-block:: console

nsh> pwm -f 1000 -d 50 -t 5

The current port is still intentionally small. In particular:
This command starts a 1 kHz PWM waveform with a 50% duty cycle for 5 seconds.
On the default channel that corresponds to a 1 ms period with a 500 us high
pulse on ``PA6``. A typical console log is:

* only the ``nsh`` board configuration is maintained
* only USART1 routing is described by the board port
* LEDs are supported, but board buttons are not yet implemented
* internal GPIO helpers exist, but there is not yet a board-level ``/dev/gpio``
test interface in this port
.. code-block:: console

nsh> pwm -f 1000 -d 50 -t 5
pwm_main: starting output with frequency: 1000 duty: 00007fff
pwm_main: stopping output

Peripheral Support
==================

+---------------------+---------+-------------------------------------+
| Peripheral | Support | Notes |
+=====================+=========+=====================================+
| Boot / Clock / IRQ | Yes | Board start-up, clock tree and tick |
+---------------------+---------+-------------------------------------+
| UART | Yes | USART1 console |
+---------------------+---------+-------------------------------------+
| GPIO | Partial | Internal helpers only |
+---------------------+---------+-------------------------------------+
| LEDs | Yes | ``USERLED`` and ``/dev/userleds`` |
+---------------------+---------+-------------------------------------+
| Buttons | No | |
+---------------------+---------+-------------------------------------+
| PWM | Yes | TMR3 exposed as ``/dev/pwm0`` |
+---------------------+---------+-------------------------------------+
| Pulse Counter | No | |
+---------------------+---------+-------------------------------------+
| Timers | Partial | OS tick and TMR3 PWM |
+---------------------+---------+-------------------------------------+
| SPI | No | |
+---------------------+---------+-------------------------------------+
| I2C | No | |
+---------------------+---------+-------------------------------------+
| ADC | No | |
+---------------------+---------+-------------------------------------+
| DAC | No | |
+---------------------+---------+-------------------------------------+
| CAN | No | |
+---------------------+---------+-------------------------------------+
| DMA | No | |
+---------------------+---------+-------------------------------------+
| RTC / ERTC | No | |
+---------------------+---------+-------------------------------------+
| I2S | No | |
+---------------------+---------+-------------------------------------+
| Watchdog | No | |
+---------------------+---------+-------------------------------------+
| USB Device | No | |
+---------------------+---------+-------------------------------------+
| USB Host | No | |
+---------------------+---------+-------------------------------------+
| External Interrupts | No | |
+---------------------+---------+-------------------------------------+
| Power Control | No | |
+---------------------+---------+-------------------------------------+

Configurations
==============
Expand Down Expand Up @@ -175,3 +240,46 @@ And the built-in applications can be listed with:
nsh
ostest
sh

pwm
---

This configuration enables the generic PWM framework, registers the TMR3
lower-half driver as ``/dev/pwm0`` .. ``/dev/pwm3``, and includes the ``pwm`` example
application for board-level validation.

Configure and build it from the ``nuttx`` directory:

.. code-block:: console

$ ./tools/configure.sh -l esk32:pwm
$ make olddefconfig
$ make -j

After flashing the image, the following command can be used from NSH to
validate PWM generation on ``/dev/pwm0``:

.. code-block:: console

nsh> pwm -f 1000 -d 50 -t 5

The expected result is a 1 kHz, 50% duty-cycle waveform on ``PA6`` for 5
seconds, followed by the application stopping the output. A typical console
log is:

.. code-block:: console

nsh> pwm -f 1000 -d 50 -t 5
pwm_main: starting output with frequency: 1000 duty: 00007fff
pwm_main: stopping output

The additional TMR3 outputs are also registered:

* ``/dev/pwm0``: ``PA6`` / TMR3_CH1
* ``/dev/pwm1``: ``PA7`` / TMR3_CH2
* ``/dev/pwm2``: ``PB0`` / TMR3_CH3
* ``/dev/pwm3``: ``PB1`` / TMR3_CH4

All four device nodes share the same underlying TMR3 instance, so they must
run at the same PWM frequency. Starting one channel at a different frequency
while another channel is active returns ``-EBUSY``.
4 changes: 4 additions & 0 deletions arch/arm/src/ht32f491x3/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,10 @@ list(
ht32f491x3_lowputc.c
ht32f491x3_serial.c)

if(CONFIG_PWM)
list(APPEND SRCS ht32f491x3_pwm.c)
endif()

if(CONFIG_ARCH_HAVE_CUSTOM_VECTORS)
list(APPEND SRCS arm_vectors.c)
endif()
Expand Down
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