Orangutan SVP-1284 Servo connection question

Ok, on this page https://www.pololu.com/docs/0J20/6.i under part two labeled “2. svp-eight-servo” it says…

 *This example uses the OrangutanServos functions to control eight servos.
 * To use this example, you must connect the correct AVR I/O pins to their
 * corresponding servo demultiplexer output-selection pins.
 *   - Connect PB3 to SA.
 *   - Connect PB4 to SB.
 *   - Connect PC0 to SC."

…Now I understand that I need to connect PB3 to SA, so on and so forth but what I do not understand, is what this should look like. Could someone upload a picture for me to reference? I have the reference diagram and have looked it over but, Timer 0 PWM outputs has three female connectors in that line. Also in the same section on the same page it says…

// This array specifies the correspondence between I/O pins and DEMUX
// output-selection pins.  This demo uses three pins, which allows you
// to control up to 8 servos.  You can also use two, one, or zero pins
// to control fewer servos."

…Does this mean that if, for instance I have 8 servos connected to servo 0,1,2,3,4,5,6,7 pins that I don’t have to connect the AVR I/O pins to their corresponding servo demultiplexer output selection pins? I can control the servos directly from the servo 0,1,2,3,4,5,6,7 pins? Sorry for the ultra-n00b question. I am just trying to wrap my head around this entire thing. I havn’t ever done any kind of work with a micro-controller before nor have I ever done any code writing so this is all a foreign language to me. I will get it though with y’alls help. Thanks in advance.

Hello, Skumdog.

I’m not sure why you are talking about Timer 0 PWM outputs. In that example code, we are not using PB4 or PB3 as PWM outputs, we are just using them as general purpose I/O (so any AVR I/O pin can be used).

Please look carefully at the key of the Orangutan SVP Reference Diagram to understand what’s going on. PB3 and PB4 and PC0 are I/O pins. I/O pins are represented by a white circle with a black border. We provide ground and power connects near the I/O pins for convenience, but you do not need to connect anything to them today.

After you’ve identified what pins you need to connect, you should see what type of headers are soldered to those pins on your board. If you have the assembled Orangutan SVP-1284 then are the pins you need to connect will have female header attached to them. To attach two pins that have female headers, you need a wire with two male ends, such as:

No. You can use two, one, or zero pins to control fewer servos.


Here’s what I would do if I were in your situation and wanted to understand things better. I would go to the Orangutan SVP Schematic and look at the relevant parts on pages 3 and 1. I would notice that the part number of servo demultiplexer is 74HC238. Then I would go to the datasheet of the 74HC238 demultiplexer and learn about what the demultiplexer itself is, in isolation from the SVP. Please note that the A0, A1, and A2 inputs of the demultiplexer are not connected to any AVR I/O pins by default, so if you want to control them you have to make extra connections. They are connected to the SVP pins labeled SA, SB, and SC. Please note that the E3 input is connected to the “SERVO” node which is connected to PD5 on the AVR, which is a PWM output.

Also, on the page you linked to, did you read this paragraph?


Ok thank you. I think I just read so much on it last night that all the info in my brain was all garbled. Thank you for the clarification. Like I said I am new to all of this, electronics and programming. I want to learn as much as possible about it. So again thanks.