| More Details:
- Up to 84 channels of digital input, digital output, and servo output
- Up to 36 channels of 10-bit analog input
- Refresh Rate - 20ms under all conditions
- Control and Power Interface - USB
- Drivers available for Windows, Apple, Linux and Open BSD
- Servo Power - separate terminals for voltage of your choice
A schematic of the SD84 can be found here.
The SD84 has 84 sets of 3-pin headers, in groups of 4 at a time. In all cases, the pin nearest the outside of the PCB is 0v Ground. The middle pin is +V power for the servo from the associated 2-pin screw terminals. The inside pin, nearest the CPUs is the signal pin.
Internal Registers
There are three internal registers associated with each of the 84 channels.
A "Mode" register (1 Byte) that defines the current mode of the channel, INPUT, OUTPUT_LOW, OUTPUT_HIGH, SERVO or ANALOGUE.
A "Servo" register (2 Bytes) that defines the position of the servo in μs. The "Servo" register is an integer (two bytes). The speed and low byte/high byte of the position.
A "Speed" register (1 Byte) that defines the speed of the servos while changing position.
|