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Servo Board Chaining

With the new bechele software it is possible to drive several PCA9685 PWM boards from the mini computer. One PCA9685 PCB (or chip) has 16 PWM channels. Means you can connect 16 Servos maximum per Board. If you need to drive more than 16 Servos, you may connect several boards to the mini computer. However there are a few things to consider:

  • Note that chaining several PCA9685 PWM Boards is only supported from Software version 2.0
  • Each board needs its own i2c address. The address is set via the six solder bridges: No bridge = 40h A0 set =41, A1 set= 42, A0and A1 set=43, A2 set=44…. and so on. The counting is binary counting. Maximum 64 combinations are possible. This means the maximum number of boards is 64 (64*16) =1024 servos
  • Subsequent boards need to have subsequent i2c addresses.
  • With the SD card images provided, the first board uses i2c address 40h. This means the first board has 40h the second 41h, the third 42h and so on ..
  • Do !!! NOT !!! chain the Servo Power from one board to the other, even if the the plugs and headers suggest. You will otherwise very likely run into trouble with interferences from the power lines. Best is to have for each board its own power supply line.