Horner-apg XLt OCS Manual do Utilizador descarregar pdf (Página 45)

MAN0878-04-EN CH. 10

August 12, 2009 Page 45 of 100 ECN # 979

10.3 HSC Functions Register Map

%AI5-6 HSC1 (function) Accumulator Quad 1 Acc

%AI7-8 HSC2 (function) Accumulator

%AI9-10 HSC3 (function) Accumulator Quad 2 Acc

%AI11-12 HSC4 (function) Accumulator

%AQ1-2 HSC1 Preset

%AQ3-4

HSC2 Preset

%Q17 Clear HSC1 Clear Quad 1

%Q18 Clear HSC2 Set Quad 1

%Q19 Clear HSC3 Clear Quad 2

%Q20

Clear HSC4

Set Quad 2

10.4 Pulse Width Modulation (PWM) Functions

On units that support the PWM, two dedicated outputs are available that can be configured for one of four

modes of operation. Those modes are Normal, PWM, HSC (count = PV) and Stepper.

10.4.1 Normal

When either Q1 or Q2 is configured for Normal operation, the digital output registers %Q1 and

%Q2 drives that respective output.

10.4.2 PWM

When either Q1 or Q2 is configured for PWM, the PWM function drives that respective output.

Both PWM channels may be individually enabled; however, when both PWM outputs are

enabled, both share the same output frequency (with the low going pulses synchronized).

Otherwise, each PWM’s pulse width can be independently adjusted.

The PWMs require three parameters (%AQs) to be set for operation. These parameters may be set at

run-time.

• Prescale Count

The prescale (%AQ5-6) count sets the resolution of the internal counter used for generating the

PWM output. The (prescale count + 1) is a divisor applied to a 16MHz clock that drives the

internal PWM counter. For the highest resolution PWM output, this value should be set as low as

possible (0 provides a 1/16 micro second resolution). Both the Period and Duty cycle (pulse

width) are based on counts of the internal PWM counter.

The frequency of the PWM output is calculated using the following formula:

Frequency =

()

tPeriodCountescaleCoun ×+1Pr

000,000,16

1 2 ... 40 41 42 43 44 45 46 47 48 49 50 ... 99 100

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Horner-apg XLt OCS Manual do Utilizador Página 45