![Freescale Semiconductor PXR4030 Скачать руководство пользователя страница 1081](http://html1.mh-extra.com/html/freescale-semiconductor/pxr4030/pxr4030_reference-manual_23306601081.webp)
Enhanced Queued Analog-to-Digital Converter (EQADC)
Freescale Semiconductor
27-99
PXR40 Microcontroller Reference Manual, Rev. 1
there is 1 ADC clock cycle for each bit of resolution. Therefore, for the same ADC clock frequency, the
ADC sample frequency is higher for lower resolutions.
27.7.6.6
ADC Calibration Feature
27.7.6.6.1
Overview
There are three sets of calibration coefficients for each ADC. Each set is composed by a gain factor and
an offset factor: GCCn/OCCn, ALTGCCn1/ALTGCCn1, and ALTGCCn2/ALTGCCn2, where n is the
ADC number 0 or 1. The pair GCCn/OCCn is selected when it is used the normal configuration or the
alternate configurations 3 to 8. The pair ALTGCCn1/ALTGCCn1 is used only when the alternate
configuration 1 is selected. And the pair ALTGCCn2/ALTGCCn2 is for the alternate configuration 2. The
description below is for a generic pair of gain/offset GCC/OCC.
The EQADC provides a calibration scheme to remove the effects of gain and offset errors from the results
generated by the on-chip ADCs. Only results generated by the on-chip ADCs are calibrated. The results
generated by ADCs on the external device are directly sent to RFIFOs unchanged. The main component
of calibration hardware is a Multiply-and-Accumulate (MAC) unit, one per on-chip ADC, that is used to
calculate the following transfer function which relates a calibrated result to a raw, uncalibrated one.
CAL_RES = GCC * R OCC+2;
where:
•
CAL_RES is the calibrated result corresponding the input voltage V
i
.
•
GCC is the gain calibration constant.
•
RAW_RES is the raw, uncalibrated result with resolution adjustment corresponding to an specific
input voltage V
i
.
•
OCC is the offset calibration constant.
•
The addition of two reduces the maximum quantization error of the ADC. See
Quantization Error Reduction During Calibration
Calibration constants GCC and OCC are determined by taking two samples of known reference voltages
and using these samples to calculate the values for the constants. For details and an example about how to
calculate the calibration constants and use them in result calibration refer to
. Once calculated, GCC is stored in the
Section 27.6.3.4, ADC0/1 Gain Calibration Constant
Registers (ADC0_GCCR and ADC1_GCCR)
, and OCC in
Section 27.6.3.5, ADC0/1 Offset Calibration
Constant Registers (ADC0_OCCR and ADC1_OCCR)
, from where their values are fed to the MAC unit.
The alternate gain values are stored in
Section 27.6.3.7, ADC0/1 Alternate Gain Registers
, and the alternate offset values in
Alternate Offset Register (ADC0_AOR1-2 and ADC1_AOR1-2)
. Since the analog characteristics of each
on-chip ADCs differs, each ADC has an independent pair of calibration constants.
A conversion result is calibrated according to the status of CAL bit in the command that initiated the
conversion. If the CAL bit is asserted, the EQADC will automatically calculate the calibrated result before
sending the result to the appropriate RFIFO or companion module. If the CAL bit is negated, the result is
not calibrated, it bypasses the calibration hardware, and is directly sent to the appropriate RFIFO or
companion module.
Содержание PXR4030
Страница 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Страница 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Страница 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Страница 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Страница 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 158: ...Power Management Controller PMC 5 26 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 182: ...Frequency Modulated Phase Locked Loop FMPLL 6 24 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 278: ...System Integration Unit SIU 7 96 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 280: ...System Information Module PXR40 Microcontroller Reference Manual Rev 1 8 2 Freescale Semiconductor...
Страница 300: ...Boot Assist Module BAM 9 20 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 346: ...Interrupts and Interrupt Controller INTC 10 46 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 352: ...General Purpose Static RAM SRAM 11 6 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 432: ...Core e200z7 Overview PXR40 Microcontroller Reference Manual Rev 1 13 44 Freescale Semiconductor...
Страница 460: ...Peripheral Bridge PBRIDGE 15 16 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 478: ...Memory Protection Unit MPU 16 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 496: ...Error Correction Status Module ECSM 17 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 524: ...Periodic Interrupt Timer PIT_RTI 20 12 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 740: ...FlexRay Communication Controller FLEXRAY 22 156 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 928: ...Deserial Serial Peripheral Interface DSPI 25 68 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 982: ...Enhanced Serial Communication Interface eSCI 26 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1114: ...Enhanced Queued Analog to Digital Converter EQADC 27 132 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1262: ...Enhanced Time Processing Unit eTPU2 29 94 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1399: ...Nexus Development Interface NDI Freescale Semiconductor 31 83 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1400: ...Nexus Development Interface NDI 31 84 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...