[RTduino][readme] correct grammar

bsp/stm32/stm32f072-st-nucleo/applications/arduino_pinout/README.md

@@ -52,7 +52,7 @@ This board complies with Arduino UNO pins layout. For more details, please take
 
 > Notice:
 > 
-> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timer can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
+> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timers can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
 
 > References
 > 

bsp/stm32/stm32f103-blue-pill/applications/arduino_pinout/README.md

@@ -61,7 +61,7 @@ For more information, please see [pins_arduino.c](pins_arduino.c) and [pins_ardu
 
 > Notice:
 > 
-> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timer can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
+> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timers can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
 
 ## 3 Communication
 

bsp/stm32/stm32f401-st-nucleo/applications/arduino_pinout/README.md

@@ -52,7 +52,7 @@ This board complies with Arduino UNO pins layout. For more details, please take
 
 > Notice:
 > 
-> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timer can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
+> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timers can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
 
 > References
 > 

bsp/stm32/stm32f412-st-nucleo/applications/arduino_pinout/README.md

@@ -55,7 +55,7 @@ This board complies with Arduino UNO pins layout. For more details, please take
 
 > Notice:
 > 
-> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timer can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
+> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timers can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
 
 > References
 > 

bsp/stm32/stm32f469-st-disco/applications/arduino_pinout/README.md

@@ -56,7 +56,7 @@ This board complies with Arduino UNO pins layout. For more details, please take
 
 > Notice:
 > 
-> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timer can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
+> 1. Don't use a same hardware timer to drive PWM (analogRead) and servos at same time, because hardware timers can only generate a same frequency for 4 PWM channels. Otherwise, it could cause a failure when drive servos.
 
 > References
 >