Arduino Uno Rev 3.USB Serial vs RX-TX pins

Hi!
I want to control a digital servo with the arduino uno rev. 3.

I want to send commands from my pc to the arduino via USB. arduino should then send commands to the servo itself.

I plan to connect the rx/tx pins to the servo-circuit. Can I then still communicate with arduino via USB?

why would you connect it to these pins? theres many other options but yes ONLY if you use software serial AND another Serial to usb converter !!!! if i wanted to do that i would connect servo to any pwm pin like 9 (wait a second rx tx aren't pwm!!!!) and happily use the usb on arduino it self!

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spycatcher2k:
Not normally, Search for software serial.

So the rx/tx pins are connected to the usb uart interface and not the only io pins suitable for serial communication.
I think software serial is what I need.

kamhagh:
why would you connect it to these pins? theres many other options but yes ONLY if you use software serial AND another Serial to usb converter !!!! if i wanted to do that i would connect servo to any pwm pin like 9 (wait a second rx tx aren't pwm!!!!) and happily use the usb on arduino it self!

The DIGITAL servo I use does not need to be connected to a PWM. It sends and receives commands and information via half duplex TTL!

horle:
The DIGITAL servo I use does not need to be connected to a PWM. It sends and receives commands and information via half duplex TTL!

Well then, it would have been sensible to describe in the first post, what it was you actually wanted to do. Never mind ...

It becomes obvious that you wish to use SoftwareSerial functions on whatever pins that will work on - and obviously not pins 0 and 1 - to control the servo. Like your servo, SoftwareSerial is limited to half duplex.

Paul__B:
Well then, it would have been sensible to describe in the first post, what it was you actually wanted to do. Never mind ...

It becomes obvious that you wish to use SoftwareSerial functions on whatever pins that will work on - and obviously not pins 0 and 1 - to control the servo. Like your servo, SoftwareSerial is limited to half duplex.

I thought I did by saying that I want the arduino to send commands serially to a digital servo. I will make myself more clear next time, even if I don't know why you would come up with pwm in this context.

Thanks

oh well use software serial for your servo and use 0 and 1 for serial to pc so you dont need buying anything !!!!
The DIGITAL servo I use does not need to be connected to a PWM. It sends and receives commands and information via half duplex TTL!
sorry my asnwer was wrongly in the Qs!!!!

horle:
I don't know why you would come up with pwm in this context.

There are very common widely used digital servos which are controlled by the same 50 Hz pwm signal as conventional analog servos. Its reasonable to suppose that might be what you meant by a digital servo - even though you also said it has a serial interface, it wouldn't be the first time somebody misunderstood how their hardware worked and gave misleading information.

If the servo really has a TTL serial interface as you seem to be saying then I wonder what the Arduino is for. A USB-to-TTL serial adapter would be all you need to connect it directly to the PC.

There are very common widely used digital servos which are controlled by the same 50 Hz pwm signal as conventional analog servos. Its reasonable to suppose that might be what you meant by a digital servo - even though you also said it has a serial interface, it wouldn't be the first time somebody misunderstood how their hardware worked and gave misleading information.

I must agree with peter all the servos (digital or analog) I could find and all the write ups say that they take the same control input. You should provide a link to the servo you have.

Mark

can't you just use lets say 9and8 pins for software serial and connect servo to these and use 0 and 1 for serial to pc whtiout addition software