Atmel SAM4S-XPLD Atmel ATSAM4S-XPLD ATSAM4S-XPLD Hoja De Datos

 775

SAM4S [DATASHEET]

11100E–ATARM–24-Jul-13

The output controller defines the output level changes on TIOA and TIOB following an event. TIOB control is used only if
TIOB is defined as output (not as an external event).

The following events control TIOA and TIOB: software trigger, external event and RC compare. RA compare controls
TIOA and RB compare controls TIOB. Each of these events can be programmed to set, clear or toggle the output as
defined in the corresponding parameter in TC_CMR.

The quadrature decoder logic is driven by TIOA0, TIOB0, TIOB1 input pins and drives the timer/counter of channel 0 and
1. Channel 2 can be used as a time base in case of speed measurement requirements (refer to 

When writing 0 in the QDEN field of the TC_BMR register, the quadrature decoder logic is totally transparent.

TIOA0 and TIOB0 are to be driven by the 2 dedicated quadrature signals from a rotary sensor mounted on the shaft of
the off-chip motor.

A third signal from the rotary sensor can be processed through pin TIOB1 and is typically dedicated to be driven by an
index signal if it is provided by the sensor. This signal is not required to decode the quadrature signals PHA, PHB.

TCCLKS field of TC_CMR channels must be configured to select XC0 input (i.e. 0x101). TC0XC0S field has no effect as
soon as quadrature decoder is enabled.

Either speed or position/revolution can be measured. Position channel 0 accumulates the edges of PHA, PHB input
signals giving a high accuracy on motor position whereas channel 1 accumulates the index pulses of the sensor,
therefore the number of rotations. Concatenation of both values provides a high level of precision on motion system
position.

In speed mode, position cannot be measured but revolution can be measured.

Inputs from the rotary sensor can be filtered prior to down-stream processing. Accommodation of input polarity, phase
definition and other factors are configurable.

Interruptions can be generated on different events.

A compare function (using TC_RC register) is available on channel 0 (speed/position) or channel 1 (rotation) and can
generate an interrupt by means of the CPCS flag in the TC_SR registers.