This is revision C of the Servo4 module.
The Servo4 module can control up to 4 servos with complete opto isolation. The reason for the optoisolation is to prevent power surges from the servos from accidentally triggering voltage spikes on the logic power bus.
Bill Benson is providing additional Servo4 documentation.
There is a separate programming table for this module.
If you program in Easy-C, there is an access library.
The schematic for the Servo4 module is shown below:
The bus is connected to the 2×5 shrouded conenctor N5. The two CAN bus signals are fed into the PCP2551 CAN bus transceiver U2. The output of U2 is fed to the UART transmit and receive signals on the PIC16F688 microcontroller U1. The four signal wires RC0-RC3 are connected to the light emmitting diodes of U3 through 470 Ohm current limiting resistors R1-4. BPWR (pins 1 and 10) and BGND (pins 2 and 9) from N5 are routed to pins 2 and 1 respectively on connectors N1-4 to provide power for the servos. The servo signal wires are pulled to BGND via the 10K Ohm resistors R1-4. Whenever the one of the light emitting diodes in U3 is activated, the corresponding NPN transistor in U3 pulls the servo signal up to BPWR.
The printed circuit board files are listed below:
I found the following servo lead table at: http://www.sentex.net/~mec1995/hobby/leads.htm. I suspect that one of these days, the page will disappear, so I decided to make a local copy.
Radio Brand Positive Signal Negative Futaba Red White Black JR Red Orange Brown Hitec Red Yellow Black Airtronics Red Orange Black Fleet Red White Black
The following files are available:
Any fabrication issues that come up are to be listed here.