Strobe Event Latch (Qepctl[Sel] = 1) - Texas Instruments Concerto F28M36 Series Technical Reference Manual

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Position Counter and Control Unit (PCCU)

Strobe Event Latch

The position-counter value is latched to the QPOSSLAT register on the rising edge of the strobe input by

clearing the QEPCTL[SEL] bit.

If the QEPCTL[SEL] bit is set, then the position counter value is latched to the QPOSSLAT register on the

rising edge of the strobe input for forward direction and on the falling edge of the strobe input for reverse

direction as shown in

The strobe event latch interrupt flag (QFLG[SEL) is set when the position counter is latched to the

QPOSSLAT register.

9.4.3 Position Counter Initialization

The position counter can be initialized using following events:

Strobe event

Software initialization

Index Event Initialization (IEI)— The QEPI index input can be used to trigger the initialization of the

position counter at the rising or falling edge of the index input. If the QEPCTL[IEI] bits are 10, then

the position counter (QPOSCNT) is initialized with a value in the QPOSINIT register on the rising

edge of index input. Conversely, if the QEPCTL[IEI] bits are 11, initialization will be on the falling

edge of the index input.

Strobe Event Initialization (SEI)— If the QEPCTL[SEI] bits are 10, then the position counter is initialized

with a value in the QPOSINIT register on the rising edge of strobe input.

If QEPCTL[SEL] bits are 11, then the position counter is initialized with a value in the QPOSINIT

input for reverse direction.

Software Initialization (SWI)— The position counter can be initialized in software by writing a 1 to the

QEPCTL[SWI] bit. This bit is not automatically cleared. While the bit is still set, if a 1 is written to it

again, the position counter will be re-initialized.

C28 Enhanced QEP (eQEP) Module

Figure 9-11. Strobe Event Latch (QEPCTL[SEL] = 1)

SPRUHE8E – October 2012 – Revised November 2019

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