mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 661

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

29.4.4.7 Hardware average function
The hardware average function can be enabled (AVGE=1) to perform a hardware average
of multiple conversions. The number of conversions is determined by the AVGS[1:0]
bits, which select 4, 8, 16, or 32 conversions to be averaged. While the hardware average
function is in progress, the ADACT bit will be set.
After the selected input is sampled and converted, the result is placed in an accumulator
from which an average is calculated once the selected number of conversions has been
completed. When hardware averaging is selected, the completion of a single conversion
will not set the COCO bit.
If the compare function is either disabled or evaluates true, after the selected number of
conversions are completed, the average conversion result is transferred into the data
result registers, Rn, and the COCO bit is set. An ADC interrupt is generated upon the
setting of COCO if the respective ADC interrupt is enabled (AIEN=1).
29.4.5 Automatic compare function
The compare function can be configured to check if the result is less than or greater-than-
or-equal-to a single compare value, or if the result falls within or outside a range
determined by two compare values. The compare mode is determined by ACFGT,
ACREN, and the values in the compare value registers (CV1 and CV2). After the input is
sampled and converted, the compare values (CV1 and CV2) are used as described in the
following table.There are six compare modes as shown in the following table.
Freescale Semiconductor, Inc.
ACFGT
0
1
The hardware average function can perform conversions on a
channel while the MCU is in Wait or Normal Stop modes. The
ADC interrupt wakes the MCU when the hardware average is
completed if SC1n[AIEN] bit was set.
ACREN
MCF51JF128 Reference Manual, Rev. 2, 03/2011
0
0
Table 29-61. Compare modes
Table continues on the next page...
ADCCV1 relative to
Preliminary
ADCCV2
Note
—
—
Less than threshold
Greater than or equal
to threshold
Function
Chapter 29 Analog-to-Digital Converter (ADC)
Compare true if the
result is less than the
CV1 registers.
Compare true if the
result is greater than or
equal to CV1 registers.
Compare mode
description
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