pwm_cycle_time: New module for output pins with dynamic cycle times

Remove support for changing the cycle time of pwm pins from the
output_pin module.  Use a new pwm_cycle_time module that supports
setting dynamic cycle times.  This simplifies the output_pin code and
low-level pin update code.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 123 insertions, 0 deletions

diff --git a/klippy/extras/pwm_cycle_time.py b/klippy/extras/pwm_cycle_time.py
new file mode 100644
index 00000000..cebbec75
--- /dev/null
+++ b/klippy/extras/pwm_cycle_time.py
@@ -0,0 +1,123 @@
+# Handle pwm output pins with variable frequency
+#
+# Copyright (C) 2017-2023  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+PIN_MIN_TIME = 0.100
+MAX_SCHEDULE_TIME = 5.0
+
+class MCU_pwm_cycle:
+    def __init__(self, pin_params, cycle_time, start_value, shutdown_value):
+        self._mcu = pin_params['chip']
+        self._cycle_time = cycle_time
+        self._oid = None
+        self._mcu.register_config_callback(self._build_config)
+        self._pin = pin_params['pin']
+        self._invert = pin_params['invert']
+        if self._invert:
+            start_value = 1. - start_value
+            shutdown_value = 1. - shutdown_value
+        self._start_value = max(0., min(1., start_value))
+        self._shutdown_value = max(0., min(1., shutdown_value))
+        self._last_clock = self._cycle_ticks = 0
+        self._set_cmd = self._set_cycle_ticks = None
+    def _build_config(self):
+        cmd_queue = self._mcu.alloc_command_queue()
+        curtime = self._mcu.get_printer().get_reactor().monotonic()
+        printtime = self._mcu.estimated_print_time(curtime)
+        self._last_clock = self._mcu.print_time_to_clock(printtime + 0.200)
+        cycle_ticks = self._mcu.seconds_to_clock(self._cycle_time)
+        if self._shutdown_value not in [0., 1.]:
+            raise self._mcu.get_printer().config_error(
+                "shutdown value must be 0.0 or 1.0 on soft pwm")
+        if cycle_ticks >= 1<<31:
+            raise self._mcu.get_printer().config_error(
+                "PWM pin cycle time too large")
+        self._mcu.request_move_queue_slot()
+        self._oid = self._mcu.create_oid()
+        self._mcu.add_config_cmd(
+            "config_digital_out oid=%d pin=%s value=%d"
+            " default_value=%d max_duration=%d"
+            % (self._oid, self._pin, self._start_value >= 1.0,
+               self._shutdown_value >= 0.5, 0))
+        self._mcu.add_config_cmd(
+            "set_digital_out_pwm_cycle oid=%d cycle_ticks=%d"
+            % (self._oid, cycle_ticks))
+        self._cycle_ticks = cycle_ticks
+        svalue = int(self._start_value * cycle_ticks + 0.5)
+        self._mcu.add_config_cmd(
+            "queue_digital_out oid=%d clock=%d on_ticks=%d"
+            % (self._oid, self._last_clock, svalue), is_init=True)
+        self._set_cmd = self._mcu.lookup_command(
+            "queue_digital_out oid=%c clock=%u on_ticks=%u", cq=cmd_queue)
+        self._set_cycle_ticks = self._mcu.lookup_command(
+            "set_digital_out_pwm_cycle oid=%c cycle_ticks=%u", cq=cmd_queue)
+    def set_pwm_cycle(self, print_time, value, cycle_time):
+        clock = self._mcu.print_time_to_clock(print_time)
+        minclock = self._last_clock
+        # Send updated cycle_time if necessary
+        cycle_ticks = self._mcu.seconds_to_clock(cycle_time)
+        if cycle_ticks != self._cycle_ticks:
+            if cycle_ticks >= 1<<31:
+                raise self._mcu.get_printer().command_error(
+                    "PWM cycle time too large")
+            self._set_cycle_ticks.send([self._oid, cycle_ticks],
+                                       minclock=minclock, reqclock=clock)
+            self._cycle_ticks = cycle_ticks
+        # Send pwm update
+        if self._invert:
+            value = 1. - value
+        v = int(max(0., min(1., value)) * float(self._cycle_ticks) + 0.5)
+        self._set_cmd.send([self._oid, clock, v],
+                           minclock=self._last_clock, reqclock=clock)
+        self._last_clock = clock
+
+class PrinterOutputPWMCycle:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.last_print_time = 0.
+        cycle_time = config.getfloat('cycle_time', 0.100, above=0.,
+                                     maxval=MAX_SCHEDULE_TIME)
+        self.last_cycle_time = self.default_cycle_time = cycle_time
+        # Determine start and shutdown values
+        self.scale = config.getfloat('scale', 1., above=0.)
+        self.last_value = config.getfloat(
+            'value', 0., minval=0., maxval=self.scale) / self.scale
+        self.shutdown_value = config.getfloat(
+            'shutdown_value', 0., minval=0., maxval=self.scale) / self.scale
+        # Create pwm pin object
+        ppins = self.printer.lookup_object('pins')
+        pin_params = ppins.lookup_pin(config.get('pin'), can_invert=True)
+        self.mcu_pin = MCU_pwm_cycle(pin_params, cycle_time,
+                                     self.last_value, self.shutdown_value)
+        # Register commands
+        pin_name = config.get_name().split()[1]
+        gcode = self.printer.lookup_object('gcode')
+        gcode.register_mux_command("SET_PIN", "PIN", pin_name,
+                                   self.cmd_SET_PIN,
+                                   desc=self.cmd_SET_PIN_help)
+    def get_status(self, eventtime):
+        return {'value': self.last_value}
+    def _set_pin(self, print_time, value, cycle_time):
+        if value == self.last_value and cycle_time == self.last_cycle_time:
+            return
+        print_time = max(print_time, self.last_print_time + PIN_MIN_TIME)
+        self.mcu_pin.set_pwm_cycle(print_time, value, cycle_time)
+        self.last_value = value
+        self.last_cycle_time = cycle_time
+        self.last_print_time = print_time
+    cmd_SET_PIN_help = "Set the value of an output pin"
+    def cmd_SET_PIN(self, gcmd):
+        # Read requested value
+        value = gcmd.get_float('VALUE', minval=0., maxval=self.scale)
+        value /= self.scale
+        cycle_time = gcmd.get_float('CYCLE_TIME', self.default_cycle_time,
+                                    above=0., maxval=MAX_SCHEDULE_TIME)
+        # Obtain print_time and apply requested settings
+        toolhead = self.printer.lookup_object('toolhead')
+        toolhead.register_lookahead_callback(
+            lambda print_time: self._set_pin(print_time, value, cycle_time))
+
+def load_config_prefix(config):
+    return PrinterOutputPWMCycle(config)