Texas Instruments Tiva TM4C123GH6PM, User Manual

Page: 177 / 352

Quadrature Encoder (QEI)
ui32MaxPosition is the maximum value of the position integrator, and is the value used to reset
the position capture when in index reset mode and moving in the reverse (negative) direction.
Returns:
None.
16.2.1.2 ROM_QEIDirectionGet
Gets the current direction of rotation.
Prototype:
int32_t
ROM_QEIDirectionGet(uint32_t ui32Base)
ROM Location:
ROM_APITABLE
is an array of pointers located at
0x0100.0010
.
ROM_QEITABLE
is an array of pointers located at
ROM_APITABLE[9]
.
ROM_QEIDirectionGet
is a function pointer located at
ROM_QEITABLE[5]
.
Parameters:
ui32Base is the base address of the quadrature encoder module.
Description:
This returns the current direction of rotation. In this case, current means the most recently
detected direction of the encoder; it may not be presently moving but this is the direction it last
moved before it stopped.
Returns:
Returns 1 if moving in the forward direction or -1 if moving in the reverse direction.
16.2.1.3 ROM_QEIDisable
Disables the quadrature encoder.
Prototype:
void
ROM_QEIDisable(uint32_t ui32Base)
ROM Location:
ROM_APITABLE
is an array of pointers located at
0x0100.0010
.
ROM_QEITABLE
is an array of pointers located at
ROM_APITABLE[9]
.
ROM_QEIDisable
is a function pointer located at
ROM_QEITABLE[2]
.
Parameters:
ui32Base
is the base address of the quadrature encoder module.
Description:
This will disable operation of the quadrature encoder module.
Returns:
None.
April 8, 2013 177