The eQEP module interfaces directly with linear or rotary incremental encoders to obtain position, direction, and speed information from rotating machines used in high-performance motion and position-control systems. There are three Type 0 eQEP modules in each Concerto device.
Each eQEP peripheral comprises five major functional blocks: Quadrature Capture Unit (QCAP), Position Counter/Control Unit (PCCU), Quadrature Decoder (QDU), Unit Time Base for speed and frequency measurement (UTIME), and Watchdog timer for detecting stalls (QWDOG). The C28x CPU controls and communicates with these modules through a set of associated registers (see Figure 5-47). The eQEP peripherals are clocked by C28SYSCLK, and its registers are accessible by the C28x CPU. This peripheral clock can be enabled or disabled by flipping a bit in one of the system control registers.
Each eQEP peripheral connects through the GPIO_MUX1 block to four device pins. Two of the four pins are always inputs, while the other two can be inputs or outputs, depending on the operating mode. The PCCU block of each eQEP also drives one interrupt to the C28x PIE. There is a total of three EQEPxINT interrupts—one from each of the three eQEP modules.