Just a guess, you probably need to consider the whole 21.7ms or 21.3ms to be your period (46Hz or 47Hz) and then your duty cycle will be 8% or 6% respectively.
On Tue, Jan 19, 2016 at 10:32 AM, J B <k1llfre...@hotmail.co.uk> wrote: > I'm trying to use the PWM module to control a parallax servo I purchased. > I'm trying to get it to spin both ways as I need it for a project, I have > tried to spin the servo both clockwise and anti clockwise but I do not know > how to set a 20ms gap between each pulse, I need 1.7ms to go anti clockwise > with a 20ms gap and 1.3ms with a 20ms gap to spin clockwise. I've converted > the ms into frequency but it doesn't change the direction. When I plug the > data cable into any pin on the entire board the servo spins clockwise, even > when plugged into PWM0 and (pwm-stop 0) being called. > > On another point is there a dedicated ground pin? I plugged the PWM0 port > into an oscilloscope and it was littered with static, according to my > electrical engineering tutor there is a bad ground and I need to earth it. > > Another another point, my LCD display still doesn't work and I don't know > what to do about it. > > The attachment is a datasheet for the servo I bought. > Thanks. > -- John Duncan