SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
The ePWM module represents one complete PWM channel composed of two PWM outputs: EPWMxA and EPWMxB. Multiple ePWM modules are instanced within a device as shown in Figure 19-1. Each ePWM instance is identical with one exception. Some instances include a hardware extension that allows more precise control of the PWM outputs. This extension is the high-resolution pulse width modulator (HRPWM) and is described in Section 19.15. See the device data sheet to determine which ePWM instances include this feature. Each ePWM module is indicated by a numerical value starting with 1. For example, ePWM1 is the first instance and ePWM3 is the third instance in the system and ePWMx indicates any instance.
The ePWM modules are chained together by way of a clock synchronization scheme that allows them to operate as a single system when required. Additionally, this synchronization scheme can be extended to the capture peripheral submodules (eCAP). The number of submodules is device-dependent and based on target application needs. Submodules can also operate standalone.
Each ePWM module supports the following features:
Each ePWM module is connected to the input/output signals shown in Figure 19-1. The signals are described in detail in subsequent sections.
The order in which the ePWM modules are connected can differ from what is shown in Figure 19-1. See Section 19.4.3.3 for the synchronization scheme for a particular device. Each ePWM module consists of eight submodules and is connected within a system by way of the signals shown in Figure 19-2.
Figure 19-3 shows more internal details of a single ePWM module. The main signals used by the ePWM module are:
The PWM output signals are made available external to the device.
These input signals alert the ePWM module of fault conditions external to the ePWM module. Each submodule on a device can be configured to either use or ignore any of the trip-zone signals. The TZ1 to TZ3 trip-zone signals can be configured as asynchronous inputs through the GPIO peripheral using the Input X-BAR logic, refer to Figure 19-51. TZ4 is connected to an inverted EQEPx error signal (EQEPxERR), which can be generated from any one of the EQEP submodule (for those devices with an EQEP module). TZ5 is connected to the system clock fail logic, and TZ6 is connected to the EMUSTOP output from the CPU. This allows configuring a trip action when the clock fails or the CPU halts.
Each ePWM module can be synchronized with other ePWM modules or other peripherals, using EPWMSYNCINSEL. Each ePWM module can also generate a synchronization output signal. The source of the EPWMxSYNCOUT can be selected and enabled by EPWMSYNCOUTEN and TBCTL2.OSHTSYNCMODE. For more information, see Section 19.4.3.3.
Each ePWM module also generates another PWMSYNC signal called EPWMxSYNCPER. EPWMxSYNCPER goes to the GPDAC and CMPSS for synchronization purposes. Functionality is configured using the HRPCTL register, but has no relation with the HRPWM. For more information on how EPWMxSYNCPER is used by the GPDAC and CMPSS, see the respective chapters.
Each ePWM module has two ADC start of conversion signals. Any ePWM module can trigger a start of conversion. Whichever event triggers the start of conversion is configured in the event-trigger submodule of the ePWM.
Output signals from the comparator module can be fed through the Input X-BAR and EPWM X-BAR to one or all of the 12 trip inputs [TRIPIN1-TRIPIN12] and in conjunction with the trip zone signals can generate digital compare events.
The peripheral bus is 32-bits wide and allows both 16-bit and 32-bit writes to the ePWM register file.