- Reads the status of external sensors and servo drives and sends it to the PC.
- Receives commands from the PC and writes them to external devices and servo drives.
Internal structure of the motion-control FPGA:
- command-pulse-generator module: generating command pulses for servo drives.
- quadrature-counter module: counting quadrature pulses from servo drives.
- output-latch module: latching parallel output signals to external devices and servo drives.
- input-latch module: latching parallel input signals from external sensors and servo drives.
- USB-interface module: reading/writing data from/to USB bus.
- Finite-state-machine module: controlling the data flows among the above modules.
1. Typical structure of motion control boards
2. Structure of “advanced” motion control boards
3. Structure of a “simple” FPGA-based motion control board
- Function blocks of the FPGA:
(1) command pulse generator
(2) encoder pulse counters
(3) I/O latches