PWM.rst: Use a power-of-2 constants.

Signed-off-by: IhorNehrutsa <[email protected]>

docs/esp32/tutorial/pwm.rst

@@ -17,12 +17,12 @@ low all of the time.
     from machine import Pin, PWM
     try:
         F = 10000  # Hz
-        D = 2**16 // 16  # 6.25%
+        D = 65536 // 16  # 6.25%
         pins = (2, 4, 12, 13, 14, 15, 16, 18, 19, 22, 23, 25, 26, 27, 32, 33)
         pwms = []
         for i, pin in enumerate(pins):
             f = F * (i // 2 + 1)
-            d = min(2**16 - 1, D * (i + 1))
+            d = min(65535, D * (i + 1))
             pwms.append(PWM(pin, freq=f, duty_u16=d))
             sleep(2/f)
             print(pwms[i])
@@ -111,7 +111,7 @@ low all of the time.
     from time import sleep
     from machine import Pin, PWM
 
-    DUTY_MAX = 2**16 - 1
+    DUTY_MAX = 65535
 
     duty_u16 = 0
     delta_d = 256
@@ -172,10 +172,10 @@ low all of the time.
     from machine import Pin, PWM
 
     try:
-        DUTY_MAX = 2**16 - 1
+        DUTY_MAX = 65535
 
         duty_u16 = 0
-        delta_d = 2**16 // 32
+        delta_d = 65536 // 32
 
         pwm = PWM(Pin(27))
         pwmi = PWM(Pin(32), invert=1)

docs/library/machine.PWM.rst

@@ -40,7 +40,7 @@ Constructors
    Setting *freq* may affect other PWM objects if the objects share the same
    underlying PWM generator (this is hardware specific).
    Only one of *duty_u16* and *duty_ns* should be specified at a time.
-   *invert* is available at RP2, i.MXRT, SAMD, nRF, ESP32 ports.
+   *invert* is available only on the RP2, i.MXRT, SAMD, nRF, ESP32 ports.
 
 Methods
 -------
@@ -76,10 +76,10 @@ Methods
    Use functions like these to convert percentages to u16 and back::
 
       def percents_to_u16(percents:int)->int:
-          return (percents * 2**16 + 50) // 100
+          return (percents * 65535 + 50) // 100
 
       def u16_to_percents(u16:int)->int:
-          return (u16 * 100 + 2**15) // 2**16
+          return (u16 * 100 + 32767) // 65535
 
 .. method:: PWM.duty_ns([value])
 
@@ -124,10 +124,10 @@ Limitations of PWM
   resolution of 8 bit, not 16-bit as may be expected.  In this case, the lowest
   8 bits of *duty_u16* are insignificant. So::
 
-    pwm=PWM(Pin(13), freq=300_000, duty_u16=2**16//2)
+    pwm=PWM(Pin(13), freq=300_000, duty_u16=65536//2)
 
   and::
 
-    pwm=PWM(Pin(13), freq=300_000, duty_u16=2**16//2 + 255)
+    pwm=PWM(Pin(13), freq=300_000, duty_u16=65536//2 + 255)
 
   will generate PWM with the same 50% duty cycle.