pwm_tool: Add support for high-speed PWM pin updates
The output_pin module is only capable of updating an output pin at most once every 100ms. Add a new pwm_tool module that is capable of queuing updates in the micro-controller and thus allowing for much higher update rates. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
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Kevin O'Connor
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48a05eaa54
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29b7550ce5
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@ -2,9 +2,8 @@
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# such as a laser or spindle.
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# See docs/Using_PWM_Tools.md for a more detailed description.
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[output_pin TOOL]
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[pwm_tool TOOL]
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pin: !ar9 # use your fan's pin number
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pwm: True
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hardware_pwm: True
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cycle_time: 0.001
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shutdown_value: 0
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@ -36,9 +35,9 @@ gcode:
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[menu __main __control __toolonoff]
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type: input
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enable: {'output_pin TOOL' in printer}
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enable: {'pwm_tool TOOL' in printer}
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name: Fan: {'ON ' if menu.input else 'OFF'}
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input: {printer['output_pin TOOL'].value}
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input: {printer['pwm_tool TOOL'].value}
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input_min: 0
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input_max: 1
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input_step: 1
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@ -47,9 +46,9 @@ gcode:
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[menu __main __control __toolspeed]
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type: input
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enable: {'output_pin TOOL' in printer}
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enable: {'pwm_tool TOOL' in printer}
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name: Tool speed: {'%3d' % (menu.input*100)}%
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input: {printer['output_pin TOOL'].value}
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input: {printer['pwm_tool TOOL'].value}
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input_min: 0
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input_max: 1
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input_step: 0.01
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@ -3127,6 +3127,26 @@ pin:
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# parameter.
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```
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### [pwm_tool]
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Pulse width modulation digital output pins capable of high speed
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updates (one may define any number of sections with an "output_pin"
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prefix). Pins configured here will be setup as output pins and one may
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modify them at run-time using "SET_PIN PIN=my_pin VALUE=.1" type
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extended [g-code commands](G-Codes.md#output_pin).
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```
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[pwm_tool my_tool]
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pin:
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# The pin to configure as an output. This parameter must be provided.
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#value:
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#shutdown_value:
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#cycle_time: 0.100
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#hardware_pwm: False
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#scale:
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# See the "output_pin" section for the definition of these parameters.
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```
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### [static_digital_output]
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Statically configured digital output pins (one may define any number
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@ -834,7 +834,8 @@ commands to manage the LED's color settings).
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### [output_pin]
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The following command is available when an
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[output_pin config section](Config_Reference.md#output_pin) is
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[output_pin config section](Config_Reference.md#output_pin) or
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[pwm_tool config section](Config_Reference.md#pwm_tool) is
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enabled.
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#### SET_PIN
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@ -318,7 +318,8 @@ is defined):
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## output_pin
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The following information is available in
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[output_pin some_name](Config_Reference.md#output_pin) objects:
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[output_pin some_name](Config_Reference.md#output_pin) and
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[pwm_tool some_name](Config_Reference.md#pwm_tool) objects:
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- `value`: The "value" of the pin, as set by a `SET_PIN` command.
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## palette2
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@ -1,7 +1,7 @@
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# Using PWM tools
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This document describes how to setup a PWM-controlled laser or spindle
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using `output_pin` and some macros.
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using `pwm_tool` and some macros.
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## How does it work?
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@ -26,14 +26,6 @@ so that when your host or MCU encounters an error, the tool will stop.
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For an example configuration, see [config/sample-pwm-tool.cfg](/config/sample-pwm-tool.cfg).
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## Current Limitations
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There is a limitation of how frequent PWM updates may occur.
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While being very precise, a PWM update may only occur every 0.1 seconds,
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rendering it almost useless for raster engraving.
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However, there exists an [experimental branch](https://github.com/Cirromulus/klipper/tree/laser_tool) with its own tradeoffs.
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In long term, it is planned to add this functionality to main-line klipper.
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## Commands
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`M3/M4 S<value>` : Set PWM duty-cycle. Values between 0 and 255.
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@ -0,0 +1,157 @@
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# Queued PWM gpio output
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#
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# Copyright (C) 2017-2023 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import chelper
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PIN_MIN_TIME = 0.100
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MAX_SCHEDULE_TIME = 5.0
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class error(Exception):
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pass
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class MCU_queued_pwm:
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def __init__(self, pin_params):
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self._mcu = pin_params['chip']
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self._hardware_pwm = False
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self._cycle_time = 0.100
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self._max_duration = 2.
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self._oid = self._mcu.create_oid()
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ffi_main, ffi_lib = chelper.get_ffi()
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self._stepqueue = ffi_main.gc(ffi_lib.stepcompress_alloc(self._oid),
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ffi_lib.stepcompress_free)
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self._mcu.register_stepqueue(self._stepqueue)
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self._stepcompress_queue_mq_msg = ffi_lib.stepcompress_queue_mq_msg
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self._mcu.register_config_callback(self._build_config)
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self._pin = pin_params['pin']
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self._invert = pin_params['invert']
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self._start_value = self._shutdown_value = float(self._invert)
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self._last_clock = self._cycle_ticks = 0
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self._pwm_max = 0.
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self._set_cmd_tag = None
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def get_mcu(self):
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return self._mcu
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def setup_max_duration(self, max_duration):
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self._max_duration = max_duration
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def setup_cycle_time(self, cycle_time, hardware_pwm=False):
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self._cycle_time = cycle_time
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self._hardware_pwm = hardware_pwm
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def setup_start_value(self, start_value, shutdown_value):
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if self._invert:
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start_value = 1. - start_value
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shutdown_value = 1. - shutdown_value
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self._start_value = max(0., min(1., start_value))
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self._shutdown_value = max(0., min(1., shutdown_value))
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def _build_config(self):
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if self._max_duration and self._start_value != self._shutdown_value:
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raise pins.error("Pin with max duration must have start"
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" value equal to shutdown value")
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cmd_queue = self._mcu.alloc_command_queue()
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curtime = self._mcu.get_printer().get_reactor().monotonic()
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printtime = self._mcu.estimated_print_time(curtime)
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self._last_clock = self._mcu.print_time_to_clock(printtime + 0.200)
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cycle_ticks = self._mcu.seconds_to_clock(self._cycle_time)
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mdur_ticks = self._mcu.seconds_to_clock(self._max_duration)
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if mdur_ticks >= 1<<31:
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raise pins.error("PWM pin max duration too large")
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if self._hardware_pwm:
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self._pwm_max = self._mcu.get_constant_float("PWM_MAX")
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self._mcu.add_config_cmd(
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"config_pwm_out oid=%d pin=%s cycle_ticks=%d value=%d"
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" default_value=%d max_duration=%d"
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% (self._oid, self._pin, cycle_ticks,
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self._start_value * self._pwm_max,
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self._shutdown_value * self._pwm_max, mdur_ticks))
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svalue = int(self._start_value * self._pwm_max + 0.5)
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self._mcu.add_config_cmd("queue_pwm_out oid=%d clock=%d value=%d"
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% (self._oid, self._last_clock, svalue),
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on_restart=True)
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self._set_cmd_tag = self._mcu.lookup_command(
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"queue_pwm_out oid=%c clock=%u value=%hu",
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cq=cmd_queue).get_command_tag()
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return
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# Software PWM
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if self._shutdown_value not in [0., 1.]:
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raise pins.error("shutdown value must be 0.0 or 1.0 on soft pwm")
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if cycle_ticks >= 1<<31:
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raise pins.error("PWM pin cycle time too large")
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self._mcu.add_config_cmd(
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"config_digital_out oid=%d pin=%s value=%d"
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" default_value=%d max_duration=%d"
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% (self._oid, self._pin, self._start_value >= 1.0,
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self._shutdown_value >= 0.5, mdur_ticks))
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self._mcu.add_config_cmd(
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"set_digital_out_pwm_cycle oid=%d cycle_ticks=%d"
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% (self._oid, cycle_ticks))
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self._cycle_ticks = cycle_ticks
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svalue = int(self._start_value * cycle_ticks + 0.5)
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self._mcu.add_config_cmd(
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"queue_digital_out oid=%d clock=%d on_ticks=%d"
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% (self._oid, self._last_clock, svalue), is_init=True)
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self._set_cmd_tag = self._mcu.lookup_command(
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"queue_digital_out oid=%c clock=%u on_ticks=%u",
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cq=cmd_queue).get_command_tag()
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def set_pwm(self, print_time, value):
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clock = self._mcu.print_time_to_clock(print_time)
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minclock = self._last_clock
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self._last_clock = clock
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if self._invert:
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value = 1. - value
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max_count = self._cycle_ticks
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if self._hardware_pwm:
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max_count = self._pwm_max
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v = int(max(0., min(1., value)) * max_count + 0.5)
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data = (self._set_cmd_tag, self._oid, clock & 0xffffffff, v)
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ret = self._stepcompress_queue_mq_msg(self._stepqueue, clock,
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data, len(data))
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if ret:
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raise error("Internal error in stepcompress")
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class PrinterOutputPin:
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def __init__(self, config):
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self.printer = config.get_printer()
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ppins = self.printer.lookup_object('pins')
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# Determine pin type
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pin_params = ppins.lookup_pin(config.get('pin'), can_invert=True)
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self.mcu_pin = MCU_queued_pwm(pin_params)
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cycle_time = config.getfloat('cycle_time', 0.100, above=0.,
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maxval=MAX_SCHEDULE_TIME)
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hardware_pwm = config.getboolean('hardware_pwm', False)
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self.mcu_pin.setup_cycle_time(cycle_time, hardware_pwm)
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self.scale = config.getfloat('scale', 1., above=0.)
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self.last_print_time = 0.
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self.mcu_pin.setup_max_duration(0.)
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# Determine start and shutdown values
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self.last_value = config.getfloat(
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'value', 0., minval=0., maxval=self.scale) / self.scale
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self.shutdown_value = config.getfloat(
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'shutdown_value', 0., minval=0., maxval=self.scale) / self.scale
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self.mcu_pin.setup_start_value(self.last_value, self.shutdown_value)
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# Register commands
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pin_name = config.get_name().split()[1]
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gcode = self.printer.lookup_object('gcode')
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gcode.register_mux_command("SET_PIN", "PIN", pin_name,
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self.cmd_SET_PIN,
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desc=self.cmd_SET_PIN_help)
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def get_status(self, eventtime):
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return {'value': self.last_value}
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def _set_pin(self, print_time, value):
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if value == self.last_value:
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return
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print_time = max(print_time, self.last_print_time)
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self.mcu_pin.set_pwm(print_time, value)
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self.last_value = value
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self.last_print_time = print_time
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cmd_SET_PIN_help = "Set the value of an output pin"
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def cmd_SET_PIN(self, gcmd):
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# Read requested value
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value = gcmd.get_float('VALUE', minval=0., maxval=self.scale)
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value /= self.scale
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# Obtain print_time and apply requested settings
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toolhead = self.printer.lookup_object('toolhead')
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toolhead.register_lookahead_callback(
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lambda print_time: self._set_pin(print_time, value))
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def load_config_prefix(config):
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return PrinterOutputPin(config)
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@ -13,6 +13,12 @@ value: 0
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shutdown_value: 0
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cycle_time: 0.01
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[pwm_tool test_pwm_tool]
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pin: PH4
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value: 0
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shutdown_value: 0
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cycle_time: 0.01
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[mcu]
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serial: /dev/ttyACM0
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@ -28,3 +28,11 @@ SET_PIN PIN=soft_pwm_pin VALUE=0.5 CYCLE_TIME=0.5
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SET_PIN PIN=soft_pwm_pin VALUE=0.5 CYCLE_TIME=0.5
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SET_PIN PIN=soft_pwm_pin VALUE=0.75 CYCLE_TIME=0.5
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SET_PIN PIN=soft_pwm_pin VALUE=0.75 CYCLE_TIME=0.75
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# PWM tool
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# Basic test
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SET_PIN PIN=test_pwm_tool VALUE=0
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SET_PIN PIN=test_pwm_tool VALUE=0.5
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SET_PIN PIN=test_pwm_tool VALUE=0.5
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SET_PIN PIN=test_pwm_tool VALUE=0.25
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SET_PIN PIN=test_pwm_tool VALUE=1
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