AN2688 Freescale Semiconductor / Motorola, AN2688 Datasheet
AN2688
Related parts for AN2688
AN2688 Summary of contents
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... Freescale Semiconductor, Inc. Application Note AN2688/D 3/2004 Implementing a 10-Bit Sigma-Delta Analog-to- Digital Converter Using the HC9S08Rx MCU Family Analog Comparator By: Jefferson Daniel de Barros Soldera Marcus Espindola Alfredo Olmos Brazilian Semiconductor Technology Center — BSTC/SPS Introduction Analog-to-digital (AD) converters, based on the Sigma-Delta (Σ∆) modulation trade resolution in time for resolution in amplitude by combining: • ...
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... Freescale Semiconductor, Inc. AN2688/D Σ∆ Modulation at a Glance illustrates the basic architecture of a Σ∆ AD converter comprising: Figure 1 • An analog integrator • A quantizer or comparator enclosed in a feedback loop via a single-bit digital-to-analog (DA) converter • A digital low-pass filter. The input signal is fed to the comparator through the integrator and the quantized output is fed back and subtracted from the input ...
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... Figure 3 allows attaining a 10-bit resolution. Since for DC or slowly Go to: www.freescale.com SD Modulation at a Glance works as a 1-bit circuit also performs low-pass anti FEEDBACK LOOP LATCH DIGITAL FILTER CK Equation Equation 2 AN2688 BITS 3 ...
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... Freescale Semiconductor, Inc. AN2688/D Implementation with HC9S08Rx MCU Family The HC9S08Rx MCU with the analog comparator function can be configured as a first-order continuous-time Σ∆ AD converter as depicted in by adding: • Two external resistors • One capacitor • Properly programming the internal timers to filter and decimate the comparator digitized output ...
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... Multiple power management modes including 20 nA power down @ 2 V Optional auto wake-up with internal timer and internal oscillator typically 700 1.8–3.6 V operation 125 ns minimum instruction cycle time down to 1 MHz bus Single wire background debug mode Trace capability with 9 trigger modes and 3 breakpoints Go to: www.freescale.com AN2688/D 5 ...
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... Freescale Semiconductor, Inc. AN2688/D • Low power oscillator capable of operating from crystal or resonator from MHz • On-chip analog comparator with internal reference (ACMP) – – • Serial communications interface module (SCI) • Serial peripheral interface module (SPI) • 2-channel, 16-bit timer/pulse width modulator (TPM) module with selectable input capture, output compare, and edge-aligned or center-aligned PWM capability on each channel ...
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... MΩ 16 MHz to: www.freescale.com Application Description Software Description 2.4 V Supply 1 µF 100 PTC0 18 30 PTC1 31 PTC2 32 PTC3 33 PTC4 9S08Rx 38 PTC5 MCU RESULTS L:H 39 PTC6 40 PTC7 46 PTB0 13 PTB1 14 PTB2 15 19 XTAL AN2688/D 7 ...
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... Freescale Semiconductor, Inc. AN2688/D The MCU oscillator is a traditional Pierce oscillator that can accommodate a crystal or ceramic resonator MHz. Resistor R resistor such as a carbon composition resistor and it’s tolerance is not critical. C and C should be ceramic capacitors being typically in the 5-pF to 25-pF range and 3 are chosen to match the requirements of a specific crystal or resonator. The crystal ...
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... Figure 7. Σ∆ Modulator Response to a Triangle Input Signal Figure 8. Σ∆ Modulator Response to a Sinusoidal Input Signal MOTOROLA Implementing a 10-Bit Sigma-Delta Analog-to-Digital Converter Using the HC9S08Rx MCU Family Analog Comparator For More Information On This Product, Go to: www.freescale.com AN2688/D Application Description 9 ...
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... Freescale Semiconductor, Inc. AN2688/D The Σ∆ modulator evaluation is performed by analyzing the single-bit output signal spectrum through the Fast Fourier Transform (FFT). Input power is normalized to the quantization step defined by the comparator supply voltage whereas the sampling rate is set to 128 kHz with the timer interruption feature. ...
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... Figure 11. Measured Σ∆ Modulator SNR for a 50-kHz Sampling Frequency MOTOROLA Implementing a 10-Bit Sigma-Delta Analog-to-Digital Converter Using the HC9S08Rx MCU Family Analog Comparator For More Information On This Product, -50 -40 -30 -20 Input power [dB] and 125-Hz Input Signal Frequency Go to: www.freescale.com AN2688/D Application Description -10 0 ...
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... Freescale Semiconductor, Inc. AN2688/D Software Description Two software options are listed in this application note. The first one is intended to implement a first-order continuous-time Σ∆ modulator according to the flowchart in Figure 12. The second one corresponds to the complete first-order continuous- time Σ∆ AD converter in Figure 12. The First-Order Σ∆ Modulator Software Flowchart ...
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... CLEAR VARIABLES FOR COUNTER AND RESULT WAIT MODE PTE0 = 0 INTERRUPT OCCURS PTE0 = 1 ACMP > PTA1 AND PTA2 = 1 INCREMENT RESULT INCREMENT COUNTER Y COUNTER < 1024? N PTE1 = 0 PTB AND PTC OUTPUT THE RESULT PTE1 = 1 Go to: www.freescale.com AN2688/D Software Description N ? REF PTA1 AND PTA2 = 0 13 ...
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... Freescale Semiconductor, Inc. AN2688/D The continuous-time Σ∆ modulator software: • Configures the I/O ports and registers • Sets the timer interrupt to a 128-kHz frequency • Clears PTE0 and the MCU stays in wait mode until an interrupt is reached. • After the timer overflows, PTE0 is set high and the comparator output flag (ACO) is verified. – ...
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... Motorola is a registered trademark of Motorola, Inc. ;******************************************************************************************* ; XDEF Entry,Reset,TPMInt ;******************************************************************************************* ;* Equates and Data Table Includes ;******************************************************************************************* include "9S08RC16.equ" MOTOROLA Implementing a 10-Bit Sigma-Delta Analog-to-Digital Converter Using the HC9S08Rx MCU Family Analog Comparator For More Information On This Product, Comments -------------------------------------------- Initial data entry Go to: www.freescale.com AN2688/D Software Listings 15 ...
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... Freescale Semiconductor, Inc. AN2688/D ;DEFAULT_RAM SECTION SHORT org RamStart ;******************************************************************************************* ;* Constants and Variables for this file ;******************************************************************************************* include 'SigmaDelta.equ' ;DEFAULT_ROM SECTION ;******************************************************************************************* ;* Code Section ;******************************************************************************************* org FlashStart Entry: Reset: ldhx #RamEndAddress+1 txs lda #setSIMOPT sta SIMOPT lda #setPMCSC1 sta PMCSC1 mov #setACMPSC,ACMPSC clr TPMCNTH clr ...
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... Timer Overflow Flag ;set bit 0 of port PTE ;clear bit 1 of port PTA ;clear bit 2 of port PTA ;return from interrupt routine ;set bit 1 of port PTA ;set bit 2 of port PTA ;return from interrupt routine Go to: www.freescale.com AN2688/D Software Listings 17 ...
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... Freescale Semiconductor, Inc. AN2688/D SignmaDeltaF.asm ;******************************************************************************************* ;* Title: SigmaDeltaF.asm (c) MOTOROLA Inc. 2004 All rights reserved. ;******************************************************************************************* ;* Author: Marcus Espindola - Motorola SPS/BSTC ;* ;* Description: Implementing a 10-bit Sigma-Delta Analog to Digital Converter Using the ;* HC9S08Rx MCU Family Analog Comparator - Code for Sigma-Delta A2D Coverter ;* ;* Documentation: 9S08RC16 Data Sheet for register and bit explanations ...
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... PTC as output ;reset Counter (low order) ;reset Counter (high order) ;reset Sample (low order) ;reset Sample (high order) ;clear bit 0 of port PTE ;clear bit 1 of port PTE ;define bit 0 of port PTE as output Go to: www.freescale.com AN2688/D Software Listings 19 ...
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... Freescale Semiconductor, Inc. AN2688/D bset DDRE1,DDRE WaitState: wait bclr PTE0,PTE bra WaitState ;******************************************************************************************* ;* Timer Interrupt (min = 48 cycles / max = 108 cycles) ;******************************************************************************************* TPMInt: lda TPMSC bclr TOF,TPMSC bset PTE0,PTE brset ACO,ACMPSC,SetOutHigh bclr PTA1,PTA bclr PTA2,PTA bra IncCounter SetOutHigh: bset PTA1,PTA bset PTA2,PTA inc SampleL ...
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... CounterH: rmb 1 CounterL: rmb 1 setSIMOPT: equ %01000001 ;System Options Register MOTOROLA Implementing a 10-Bit Sigma-Delta Analog-to-Digital Converter Using the HC9S08Rx MCU Family Analog Comparator For More Information On This Product, Copyright (c) Motorola 2004 Comments -------------------------------------------- Initial data entry Go to: www.freescale.com AN2688/D Software Listings 21 ...
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... Freescale Semiconductor, Inc. AN2688/D ; |||||||| ; |||||||+-RESET Pin Enable = 1 ; ||||||+--Background Debug Mode Pin Enable = 0 ; |||||+---Unused during write ; ||||+----Unused during write ; |||+-----Unused ; ||+------Stop Mode Enable = 0 ; |+-------COP Watchdog Timeout = Long Timeout ; +--------COP Watchdog Enable = 0 setPMCSC1: equ %01011000 ;System Power Management Status and Control 1 Register ; |||||||| ...
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... Freescale Semiconductor, Inc. MOTOROLA Implementing a 10-Bit Sigma-Delta Analog-to-Digital Converter Using the HC9S08Rx MCU Family Analog Comparator For More Information On This Product, Go to: www.freescale.com AN2688/D Software Listings 23 ...
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... Motorola and the Stylized M Logo are registered in the U.S. Patent and Trademark Office. digital dna is a trademark of Motorola, Inc. All other product or service names are the property of their respective owners. Motorola, Inc Equal Opportunity/Affirmative Action Employer. © Motorola, Inc. 2004 AN2688/D Rev. 0 3/2004 Go to: www.freescale.com ...