Driving LewanSoul LX-16A Serial Servo Directly from Particle Photon

gistfile1.txt

// GIST to outline driving this very cost effective serial servos directly from Particle Photons

// Turns out the servo uses half duplex, and requires an Open Drain
// Turn off echo, or we can't read.
// According to my nScope although the docs say pull-up to 5V I can see it's a 3.3V that's 5V tolerant
// ... just like the photon...
// So, anyway, 3.3V works just fine. Link to the TX pin (that's Serial1). RX pin is unused.
// I used an external 10K pull-up to the 3.3V pin on the photon. You might be able to do this internally too?
//
// Power the servo separately to > 6V, so be a little careful with your wiring (cos the servo power will fry your serial pin)
// I power from two 18650s, so between 7 and 8 V with a step-down to 5V for the Photon

// I use the LewanSoul libraries which you can get from their site http://bit.ly/2Arw3QM
// There is a library, but also some simple Arduino sketches, which are probably easier to hack
// You need to replace the serial device type (e.g. USARTSerial not HardwareSerial) to compile
// e.g. int LobotSerialServoReadError(USARTSerial &SerialX, uint8_t id)


// Init the serial as so.

void setup() {
  Serial1.halfduplex(true);
  Serial1.begin(115200, SERIAL_HALF_DUPLEX_OPEN_DRAIN | SERIAL_HALF_DUPLEX_NO_ECHO);
}

// The rest should be self explanatory.