Designer Systems PRODUCT DESIGN AND MANUFACTURING 18 Channel Servo Driver Shield for Arduino and Raspberry-PI Technical Data DS-SCX18.S Features Description TM The Designer Systems DS- Arduino UNO Shield SCX18.S is an eighteen 18 chan- standard form factor for simple integration into any nel RC servo driver with advanced servo control features. Arduino project TM Specifically targeted at the Ar- Frees up the Arduino IO duino UNO board user all other lines normally used for servo Arduino boards supported and the control 2 Raspberry-PI the SCX18.S fea- I C interface for simple con- 2 tures high speed I C communica- nection to Arduino or Rasp- tion for easy project integration berry-PI and smooth speed control. Dual on-board 5Volt 3Amp regulators, with heatsinking, Ni-MH battery pack of 7.2 to 8.4V Once connected each servo can be for servo power with enable and features a disable link to allow positioned (with speed control), jumpers the use of low voltage battery enabled, reversed and soft-started Sixteen (16) level speed con- packs of 3.6 to 4.8V. by simply writing a value to an trol for each servo 2 The on-board I C pull-ups are internal register over the connect- Movement complete and 2 jumper configurable to allow dis- ed I C interface. soft-start complete status for connection when connecting to the The SCX18.S caters for the major- each servo Raspberry-PI, which has its own ity of servos by providing a wide Global activation control pull-ups. pulse width range of 0.50mS to ensures all servos start mov- 2.50mS with 8uS per step accura- ing together, important for cy and also provides global activa- Applications multi-legged robots tion of new servo position, soft- The SCX18.S has applications 2 I C address links allow up to start & movement complete regis- in robotics, including quadru- four 4 shields to be used ters for superior control. ped, hexapod and octopod ro- together to provide up to 72 bots, process control & sensor servos The SCX18.S provides dual high manipulation when used in con- LVD, RoHS and WEEE power regulators capable of sup- junction with standard RC ser- compliant product plying 5V 3A to the connected vos. servos from an external Li-Pol or Selection Guide Description Part Number 18 Channel Servo Driver Shield DS-SCX18.S HS311 Standard hobby servo DS-HS311 Raspberry-PI, Arduino, NANO, UNO & MEGA are trademark. 2013 Designer Systems Page 1 of 8 CNTRL15.03.13 Revision 1.01 .co.uk CONTROL MODULES 2 To access individual registers a de- Power requirements I C connection 2 vice write must be undertaken by the The DS-SCX18.S takes the power The I C connections are marked 2 I C Master which consists of a Start necessary for operation (approx. 2- SDA and SCL and allow connec- condition, device ID (D bit 25mA) from an external battery or tion to the Arduino UNO board cleared), register to start write, one power adaptor or power from the ANALOG IN pins 4 and 5 or the or more bytes of data to be written Arduino or Raspberry-PI board. Rasperberry-PI GPIO port pins 3 2 and a stop condition (see Figure 1.0 The SCX18 provides three PCB and 5 (see Fig. 2.0) or another I C 2 for I C write protocol). pads, two marked GND and one Master device. marked Vin in the same format as There are 37 individual registers that that present on the UNO board, The DS-SCX18.S is fitted with pull- can be written within the SCX18 which should be connected to nega- up jumpers that can be configured to that control output as follows: tive and positive battery/power sup- provide the source current necessary 2 ply terminals respectively. The input for I C communication. The follow- N7 N6 N5 N4 N3 N2 N1 N0 voltage range is 4.75 - 16VDC with ing jumpers should normally be set SCX I2C address the internal circuitry being protected when using the UNO board, as long 1. 1 1 1 0 1 X X 0 2 against power supply reversal. XX = SCX18 address as the I C bus does not have existing pull-ups provided by another de- Register address R0 U U B B B B B B The two on-board servo regulators vice. These jumpers MUST be B..B = 0 to 37 provide a clean regulated 5V supply removed when using the Raspber- U..U = unused on this implementation for the connected servos at a maxi- ry-PI: Servo 1 position mum current of 3Amps each, the left R1 P P P P P P P P P..P = Servo position 0 to 255 (0.5mS to 2.50mS) hand regulator powering servos 1 to SDA Servo 1 control 9 and the right hand regulator servos R2 A B C D S S S S 10-18. The following table indicates A = Operate (0 Servo disabled 1 Servo enabled) SCL B = Reverse (0 Servo normal 1 Servo reversed) if a regulator needs to be enabled or C = Soft-start control (0 Disabled 1 Enabled) disabled dependant on supply volt- D = Speed control (0 Disabled 1 Enabled) S..S = Servo speed value 0 to 15 (0 = slowest) PULL UP age: Servo 2 position 2 R3 P P P P P P P P I C communication Status Battery pack/supply voltage P..P = Servo position 0 to 255 (0.5mS to 2.50mS) Up to four DS-SCX18.S modules Disabled 3.6V to 4.8V Servo 2 control Enabled 7.2V to 8.5V may be connected to the same UNO R4 A B C D S S S S 2 / Raspberry-PI board or I C bus and A = Operate (0 Servo disabled 1 Servo enabled) B = Reverse (0 Servo normal 1 Servo reversed) accessed individually using their The servo regulators are enabled or C = Soft-start control (0 Disabled 1 Enabled) D = Speed control (0 Disabled 1 Enabled) own individual address. disabled with on-board double links S..S = Servo speed value 0 to 15 (0 = slowest) The address is configured with the just above the regulator heat-sinks Servo 3 position following jumpers: which can be configured as follows: R5 P P P P P P P P P..P = Servo position 0 to 255 (0.5mS to 2.50mS) ADDRESS Enabled (ON): Servo 3 control R6 A B C D S S S S A0 A = Operate (0 Servo disabled 1 Servo enabled) B = Reverse (0 Servo normal 1 Servo reversed) C = Soft-start control (0 Disabled 1 Enabled) A1 D = Speed control (0 Disabled 1 Enabled) S..S = Servo speed value 0 to 15 (0 = slowest) Servo 4 position R7 P P P P P P P P The following table shows how the Disabled (OFF): P..P = Servo position 0 to 255 (0.5mS to 2.50mS) jumpers are placed for the different Servo 4 control binary addresses: R8 A B C D S S S S A = Operate (0 Servo disabled 1 Servo enabled) B = Reverse (0 Servo normal 1 Servo reversed) C = Soft-start control (0 Disabled 1 Enabled) Address xx A0 A1 D = Speed control (0 Disabled 1 Enabled) 00 (default) ON ON S..S = Servo speed value 0 to 15 (0 = slowest) 01 OFF ON Refer to the voltage rating of the Servo 5 position 10 ON OFF R9 P P P P P P P P servos you wish to use before con- 11 OFF OFF P..P = Servo position 0 to 255 (0.5mS to 2.50mS) figuring the servo regulator. Servo 5 control The binary address (xx) above is R10 A B C D S S S S Connection of the external supply - A = Operate (0 Servo disabled 1 Servo enabled) used in conjunction with the device B = Reverse (0 Servo normal 1 Servo reversed) battery / mains adaptor - to the C = Soft-start control (0 Disabled 1 Enabled) ID 11101xxD to form the complete D = Speed control (0 Disabled 1 Enabled) SCX18 module is through a two (2) device address i.e. if both jumpers S..S = Servo speed value 0 to 15 (0 = slowest) way pluggable screw terminal block are left connected (default) then the Servo 6 position marked 3-8.5VDC 6A Max. R11 P P P P P P P P device address would be P..P = Servo position 0 to 255 (0.5mS to 2.50mS) 1110100D . binary Note: This supply is NOT reverse Servo 6 control The D bit determines if a read or a R12 A B C D S S S S connection protected but is write to the SCX18 is to be per- A = Operate (0 Servo disabled 1 Servo enabled) marked with a series of +++++ B = Reverse (0 Servo normal 1 Servo reversed) formed. If the D bit is set 1 then C = Soft-start control (0 Disabled 1 Enabled) signs to denote positive. D = Speed control (0 Disabled 1 Enabled) a register read is performed or if S..S = Servo speed value 0 to 15 (0 = slowest) clear 0 a register write. 1997-2013 Designer Systems Page 2 of 8 INTERFACE 13.04.13 Revision 1.00