Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
31-62
Freescale Semiconductor
Preliminary
Figure 31-36. MAC Unit Diagram
The OCC
n
operand is a 14-bit signed value and it is the upper 14 bits of the value stored in ADC0_OCCR.
The RAW_RES operand is the raw uncalibrated result, and it is a direct output from the on-chip ADC.
The GCC
n
operand is a 15-bit fixed point unsigned value, and it is the upper 15 bits of the value stored in
ADC0_GCCR. The GCC is expressed in the
GCC_INT.GCC_FRAC
binary format. The integer part of the
GCC (GCC_INT = GCC[1]) contains a single binary digit while its fractional part
(GCC_FRAC = GCC[2:15]) contains 14 bits. See
for more information. The gain constant
equivalent decimal value ranges from 0 to 1.999938..., as shown in
. Two is always added to
the MAC output: see
Section 31.5.6.3, “Quantization Error Reduction During Calibration
output is the calibrated result, and it is a 14-bit unsigned value. CAL_RES is truncated to 0x3FFF, in case
of a overflow, and to 0x0000, in case of an underflow.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
GCC_
INT0
GCC_FRAC
Figure 31-37. Gain Calibration Constant Format
Table 31-34. Gain Calibration Constant Format Field Descriptions
Field
Description
bit 0
Reserved
GCC_INT0
Integer part of the gain calibration constant for ADC0. GCC_INT is the integer part of the gain calibration constant
(GCC) for ADC0/1.
GCC_
FRAC
Fractional part of the gain calibration constant for ADC0. GCC_FRAC is the fractional part of the gain calibration
constant (GCC) for ADC0. GCC_FRAC can expresses decimal values ranging from 0 to 0.999938...
MAC Unit
Offset Calibration Constant (OCC
n
)
(14-bit signed value from ADC0_OCCR)
Raw Uncalibrated Result (RAW_RES)
(12-bit unsigned value)
Gain Calibration Constant (GCC
n
)
(15-bit fixed point unsigned value
from ADC0_GCCR)
Calibrated Result (CAL_RES)
(14-bit unsigned value)
2
Gain Calibration Constant (GCC)
