SPRUIN7C March 2020 – March 2024 TMS320F280021 , TMS320F280021-Q1 , TMS320F280023 , TMS320F280023-Q1 , TMS320F280023C , TMS320F280025 , TMS320F280025-Q1 , TMS320F280025C , TMS320F280025C-Q1
The eQEP inputs include two pins for quadrature-clock mode or direction-count mode, an index (or 0 marker), and a strobe input. The eQEP module requires that the QEPA, QEPB, and QEPI inputs are synchronized to SYSCLK prior to entering the module. The application code can enable the synchronous GPIO input feature on any eQEP-enabled GPIO pins (see the General-Purpose Input/Output (GPIO) chapter for more details).
These two pins can be used in quadrature-clock mode or direction-count mode.
The eQEP encoder uses an index signal to assign an absolute start position from which position information is incrementally encoded using quadrature pulses. This pin is connected to the index output of the eQEP encoder to optionally reset the position counter for each revolution. This signal can be used to initialize or latch the position counter on the occurrence of a desired event on the index pin.
This general-purpose strobe signal can initialize or latch the position counter on the occurrence of a desired event on the strobe pin. This signal is typically connected to a sensor or limit switch to notify that the motor has reached a defined position.
Input signals to the eQEP (QEPA, QEPB, QEPI and QEPS) can come from multiple sources; that is, device pin, CMPSSx, or PWMXBARx. One typical use case is if SinCos transducers are used in the motor control system to estimate the position of motor shaft and Index signal is coming from traditional rotary encoder, source of the eQEP signals (QEPA, QEPB and QEPI) can be configured as output of CMPSSx that decodes the Sin, Cos, and Index signals. Figure 20-4 illustrates the use case.
Selection of the source of Input signals (QEPA, QEPB, and QEPI) is user-configurable through the QEPSRCSEL register as shown in Table 20-1.
QEPASEL, QEPBSEL, QEPISEL | Input Signal |
---|---|
0 | DEVICE_PIN |
1 | CMPSS1_CTRIPH |
2 | CMPSS2_CTRIPH |
3 | CMPSS3_CTRIPH |
4 | CMPSS4_CTRIPH |
5-7 | Reserved |
8 | ZERO |
9 | EPWMXBAR1 |
10 | EPWMXBAR2 |
11 | EPWMXBAR3 |
12 | EPWMXBAR4 |
13 | EPWMXBAR5 |
14 | EPWMXBAR6 |
15 | EPWMXBAR7 |