pwmcmds: Export the maximum PWM value

Instead of assuming the maximum PWM value is 255, export a constant
from the firmware to the host with the maximum value.

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

docs/MCU_Commands.md

@@ -50,7 +50,7 @@ Common startup commands:
   may be useful for configuring the initial value of LEDs and for
   configuring the initial value of stepper driver micro-stepping pins.
 
-* `set_pwm_out pin=%u cycle_ticks=%u value=%c` : This command will
+* `set_pwm_out pin=%u cycle_ticks=%u value=%hu` : This command will
   immediately configure the given pin to use hardware based
   pulse-width-modulation (PWM) with the given number of
   cycle_ticks. The "cycle_ticks" is the number of MCU clock ticks each
@@ -148,7 +148,7 @@ This section lists some commonly used config commands.
   feature can be used with heater pins to ensure the host does not
   enable the heater and then go off-line.
 
-* `config_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%c
+* `config_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%hu
   max_duration=%u` : This command creates an internal object for
   hardware based PWM pins that the host may schedule updates for. Its
   usage is analogous to config_digital_out - see the description of
@@ -205,11 +205,11 @@ only of interest to developers looking to gain insight into Klipper.
   same 'oid' parameter must have been issued during micro-controller
   configuration.
 
-* `schedule_pwm_out oid=%c clock=%u value=%c` : Schedules a change to
+* `schedule_pwm_out oid=%c clock=%u value=%hu` : Schedules a change to
   a hardware PWM output pin. See the 'schedule_digital_out' and
   'config_pwm_out' commands for more info.
 
-* `schedule_soft_pwm_out oid=%c clock=%u value=%c` : Schedules a
+* `schedule_soft_pwm_out oid=%c clock=%u value=%hu` : Schedules a
   change to a software PWM output pin. See the 'schedule_digital_out'
   and 'config_soft_pwm_out' commands for more info.
 

klippy/mcu.py

@@ -272,7 +272,6 @@ class MCU_digital_out:
         self.set_digital(mcu_time, dval)
 
 class MCU_pwm:
-    PWM_MAX = 255.
     def __init__(self, mcu, pin, cycle_time, hard_cycle_ticks, max_duration):
         self._mcu = mcu
         self._hard_cycle_ticks = hard_cycle_ticks
@@ -280,6 +279,7 @@ class MCU_pwm:
         pin, pullup, self._invert = parse_pin_extras(pin)
         self._last_clock = 0
         self._mcu_freq = 0.
+        self._pwm_max = 0.
         self._cmd_queue = mcu.alloc_command_queue()
         if hard_cycle_ticks:
             mcu.add_config_cmd(
@@ -297,16 +297,20 @@ class MCU_pwm:
     def build_config(self):
         self._mcu_freq = self._mcu.get_mcu_freq()
         if self._hard_cycle_ticks:
+            self._pwm_max = self._mcu.serial.msgparser.get_constant_float(
+                "PWM_MAX")
             self._set_cmd = self._mcu.lookup_command(
-                "schedule_pwm_out oid=%c clock=%u value=%c")
+                "schedule_pwm_out oid=%c clock=%u value=%hu")
         else:
+            self._pwm_max = self._mcu.serial.msgparser.get_constant_float(
+                "SOFT_PWM_MAX")
             self._set_cmd = self._mcu.lookup_command(
-                "schedule_soft_pwm_out oid=%c clock=%u value=%c")
+                "schedule_soft_pwm_out oid=%c clock=%u value=%hu")
     def set_pwm(self, mcu_time, value):
         clock = int(mcu_time * self._mcu_freq)
         if self._invert:
             value = 1. - value
-        value = int(value * self.PWM_MAX + 0.5)
+        value = int(value * self._pwm_max + 0.5)
         msg = self._set_cmd.encode(self._oid, clock, value)
         self._mcu.send(msg, minclock=self._last_clock, reqclock=clock
                       , cq=self._cmd_queue)

src/avr/gpio.c

@@ -162,6 +162,8 @@ static const uint8_t pwm_pins[ARRAY_SIZE(pwm_regs)] PROGMEM = {
 #endif
 };
 
+DECL_CONSTANT(PWM_MAX, 255);
+
 struct gpio_pwm
 gpio_pwm_setup(uint8_t pin, uint32_t cycle_time, uint8_t val)
 {

src/gpiocmds.c

@@ -90,6 +90,9 @@ DECL_COMMAND(command_set_digital_out, "set_digital_out pin=%u value=%c");
  * Soft PWM output pins
  ****************************************************************/
 
+#define MAX_SOFT_PWM 255
+DECL_CONSTANT(SOFT_PWM_MAX, MAX_SOFT_PWM);
+
 struct soft_pwm_s {
     struct timer timer;
     uint32_t on_duration, off_duration, end_time;
@@ -159,7 +162,7 @@ command_config_soft_pwm_out(uint32_t *args)
     struct soft_pwm_s *s = oid_alloc(args[0], command_config_soft_pwm_out
                                      , sizeof(*s));
     s->cycle_time = args[2];
-    s->pulse_time = s->cycle_time / 255;
+    s->pulse_time = s->cycle_time / MAX_SOFT_PWM;
     s->default_value = !!args[3];
     s->max_duration = args[4];
     s->flags = s->default_value ? SPF_ON : 0;
@@ -177,7 +180,7 @@ command_schedule_soft_pwm_out(uint32_t *args)
     uint8_t value = args[2];
     uint8_t next_flags = SPF_CHECK_END | SPF_HAVE_NEXT;
     uint32_t next_on_duration, next_off_duration;
-    if (value == 0 || value == 255) {
+    if (value == 0 || value == MAX_SOFT_PWM) {
         next_on_duration = next_off_duration = 0;
         next_flags |= value ? SPF_NEXT_ON : 0;
         if (!!value != s->default_value && s->max_duration)
@@ -208,7 +211,7 @@ command_schedule_soft_pwm_out(uint32_t *args)
     irq_enable();
 }
 DECL_COMMAND(command_schedule_soft_pwm_out,
-             "schedule_soft_pwm_out oid=%c clock=%u value=%c");
+             "schedule_soft_pwm_out oid=%c clock=%u value=%hu");
 
 static void
 soft_pwm_shutdown(void)

src/pwmcmds.c

@@ -43,7 +43,7 @@ command_config_pwm_out(uint32_t *args)
     p->max_duration = args[4];
 }
 DECL_COMMAND(command_config_pwm_out,
-             "config_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%c"
+             "config_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%hu"
              " max_duration=%u");
 
 void
@@ -57,7 +57,7 @@ command_schedule_pwm_out(uint32_t *args)
     sched_add_timer(&p->timer);
 }
 DECL_COMMAND(command_schedule_pwm_out,
-             "schedule_pwm_out oid=%c clock=%u value=%c");
+             "schedule_pwm_out oid=%c clock=%u value=%hu");
 
 static void
 pwm_shutdown(void)
@@ -75,4 +75,4 @@ command_set_pwm_out(uint32_t *args)
 {
     gpio_pwm_setup(args[0], args[1], args[2]);
 }
-DECL_COMMAND(command_set_pwm_out, "set_pwm_out pin=%u cycle_ticks=%u value=%c");
+DECL_COMMAND(command_set_pwm_out, "set_pwm_out pin=%u cycle_ticks=%u value=%hu");