Functional Description Rev. 1.04 / September 2015 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Multi-Market Sensing Platforms Precise and Deliberate ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Contents 1 2 3 4 5 Control Logic ....................................................................................................................................................... 5 1.1 General Description ...................................................................................................................................... 5 1.2 Calibration Microcontroller (CMC) ................................................................................................................ 5 1.3 General Working Modes ............................................................................................................................... 6 1.3.1 Normal Operation Mode (NOM) ............................................................................................................. 6 1.3.2 Command Mode (CM) ........................................................................................................................... 7 1.3.3 Diagnostic Mode (DM) ........................................................................................................................... 8 1.3.4 Failsafe Tasks and Error Codes ............................................................................................................ 9 Signal Conditioning ........................................................................................................................................... 11 2.1 A/D Conversion .......................................................................................................................................... 11 2.2 Digital Value Range Zooming (ZSSC3138 only) ........................................................................................ 12 2.3 Signal Conditioning Formula ...................................................................................................................... 14 2.4 Fitting Conditioning Result to Analog or Digital Output .............................................................................. 15 2.5 Digital Filter Function .................................................................................................................................. 15 2.6 Analog Output Signal Range and Limitation .............................................................................................. 16 Serial Digital Interfaces ..................................................................................................................................... 18 3.1 General Description .................................................................................................................................... 18 3.1.1 Command Structure ............................................................................................................................. 18 3.1.2 Addressing ........................................................................................................................................... 18 3.1.3 Read-Request ...................................................................................................................................... 19 3.1.4 Communication Verification ................................................................................................................. 19 3.1.5 Communication Protocol Selection ...................................................................................................... 19 3.2 Digital Output .............................................................................................................................................. 20 2 3.3 I C™ Protocol ............................................................................................................................................. 21 3.4 One-Wire Communication (OWI)................................................................................................................ 24 3.4.1 Properties and Parameters .................................................................................................................. 24 3.4.2 OWI Communication Access ............................................................................................................... 25 3.4.3 OWI Protocol ........................................................................................................................................ 26 Interface Commands ......................................................................................................................................... 29 4.1 Command Set ............................................................................................................................................. 29 4.2 Command Processing ................................................................................................................................ 32 4.3 Digital Output Data in Command Mode ...................................................................................................... 33 4.4 Detailed Description for Particular Commands .......................................................................................... 34 4.4.1 Start Command Mode with START_CM [72 D1]HEX ............................................................................ 34 4.4.2 Acquisition of Raw Measurement Data with Commands START_AD_CNT [61]HEX and START_AD_CNT_AVRG [62]HEX ......................................................................................................... 34 4.4.3 Oscillator Frequency Adjustment with ADJ_OSC_ACQ [50HEX] and ADJ_OSC_WRI [65 data]HEX .... 35 EEPROM and RAM ........................................................................................................................................... 36 5.1 Programming the EEPROM ....................................................................................................................... 36 5.2 EEPROM and RAM Contents..................................................................................................................... 36 Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 2 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 6 7 8 9 5.2.1 Traceabilty............................................................................................................................................ 38 5.2.2 EEPROM Error Correction ................................................................................................................... 39 5.3 Configuration Words ................................................................................................................................... 39 5.4 EEPROM Signature .................................................................................................................................... 43 5.5 EEPROM Write Locking ............................................................................................................................. 43 Application Recommendations: Temperature Sensor Adaption ....................................................................... 44 6.1 Temperature Measurement ........................................................................................................................ 44 6.2 On-Chip PN-Junction Temperature Sensor ............................................................................................... 44 6.3 External pn-Junction Temperature Sensor (ZSSC3135 and ZSSC3136 only) .......................................... 45 6.4 External Resistive Temperature Sensor (ZSSC3135 and ZSSC3136 only) .............................................. 46 Related Documents ........................................................................................................................................... 48 Glossary ............................................................................................................................................................ 49 Document Revision History ............................................................................................................................... 50 List of Figures Figure 1.1 Figure 1.2 Figure 2.1 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6 Figure 3.7 Figure 3.8 Figure 3.9 Measurement Cycle ............................................................................................................................... 7 Modes of Digital Serial Communication ................................................................................................. 8 Accessable Output Signal Range and Limitation ................................................................................ 16 2 I C™ Read Request during Normal Operation Mode.......................................................................... 20 2 I C™ or OWI Read Request in Diagnostic Mode ................................................................................ 20 2 I C™ or OWI Read Request Answering a Command (CM) ................................................................ 20 2 Principles of I C™ Protocol ................................................................................................................. 21 2 I C™ Write Operation .......................................................................................................................... 22 2 I C™ Read Operation (Data Request) ................................................................................................ 23 2 Timing I C™ Protocol .......................................................................................................................... 23 Block Schematic of an OWI Connection .............................................................................................. 25 Example of OWI and Actively Driven AOUT – Starting OWI Communication with a Stop Condition ..................................................................................................................................... 26 Figure 3.10 OWI Write Operation ........................................................................................................................... 27 Figure 3.11 OWI Read Operation ........................................................................................................................... 28 Figure 3.12 OWI Protocol Timing ............................................................................................................................ 28 Figure 4.1 Assignment of Check Sum for Continuously Updated Data Values .................................................... 33 Figure 4.2 START_CM Command ........................................................................................................................ 34 Figure 5.1 Source-Code Signature Generation .................................................................................................... 43 Figure 6.1 External pn-Junction Temperature Sensor (ZSSC3135 and ZSSC3136 only) ................................... 45 Figure 6.2 External Resistive Temperature Sensor (ZSSC3135 and ZSSC3136 only) ....................................... 46 Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 3 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family List of Tables Table 1.1 Table 2.1 Table 3.1 Table 3.2 Table 3.3 Table 4.1 Table 4.2 Table 4.3 Table 5.1 Table 5.2 Table 5.3 Table 5.4 Table 5.5 Table 5.6 Table 6.1 Table 6.2 Table 6.3 Table 6.4 Table 6.5 Error Detection Functionality and Error Codes ...................................................................................... 9 Valid Data Ranges for 15-bit and 16-bit ADC Resolution .................................................................... 13 2 Timing I C™ Protocol .......................................................................................................................... 23 OWI Interface Parameters ................................................................................................................... 24 OWI Protocol Parameters .................................................................................................................... 28 Command Set ...................................................................................................................................... 29 Digital Output Data Resulting from Processed Commands ................................................................ 33 Oscillator Frequency Adjust Sequence ............................................................................................... 35 EEPROM and RAM Content ................................................................................................................ 37 Lot, Wafer, x-Position, and y-Position Number Calculation Procedure ............................................... 38 Configuration Word CFGAFE .............................................................................................................. 39 Configuration Word CFGAPP .............................................................................................................. 40 Configuration Word ADJREF ............................................................................................................... 41 Configuration Word CFGSF................................................................................................................. 42 Configuration Temperature Measurement ........................................................................................... 44 Sensitivity of On-Chip Temperature Sensor ........................................................................................ 44 Sensitivity and Signal Range of the External pn-Junction Temperature Sensor ................................. 45 Signal Range Center Voltage of External pn-Junction Temperature Sensor ...................................... 45 Sensitivity and Signal Range of the External Resistive Temperature Sensor ..................................... 47 For more information, contact ZMDI via [email protected]. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 4 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 1 Control Logic Note: This document supports the ZSSC313x Automotive Resistive Sensor Signal Conditioner Family, including the ZSSC3131, ZSSC3135, ZSSC3136, and ZSSC3138. Unless otherwise noted, the term ZSSC313x refers to all of these family products. Reading the individual data sheets for these products is strongly recommended before using this document (see section 9). 1.1 General Description The control logic of the ZSSC313x consists of the calibration microcontroller (CMC), the module control logic of the analog-to-digital converter (ADC), and the serial digital interface. The configuration of the various modes of the device is done by programming settings in EEPROM. The CMC controls the measurement cycle and performs the calculations for sensor signal conditioning. This eliminates the gain deviation, the offset, the temperature deviation, and the non-linearity of the pre-amplified and A/D converted sensor signal. The A/D conversion is executed as a continuous measurement cycle. The conditioning calculation by the CMC is performed in parallel with the A/D conversion. The ZSSC313x communicates with an external microcontroller, especially for calibration purposes, via a serial 2 digital interface. A communication protocol according to the I C™* standard is supported. Additionally ZMDI’s TM ZACwire interface is implemented for one-wire communication (OWI). These serial interfaces are used for the calibration of the sensor system consisting of a transducer and the ZSSC313x. The serial interface provides the read out of the results of sensor signal conditioning as digital values during the calibration. The internal processing of received interface commands is done by the CMC. As a consequence, the measurement cycle is interrupted if a command is received. Only the read out of data is controlled by the serial interface itself and does not interrupt the CMC. 1.2 Calibration Microcontroller (CMC) The calibration microcontroller (CMC) is especially adapted to the tasks connected with the signal conditioning. The main features are The microcontroller uses 16-bit processing width and is programmed via ROM. A watchdog timer controls the proper operation of the microcontroller. Constants/coefficients for the conditioning calculation are stored in the EEPROM. The EEPROM is mirrored to the RAM after power-on or after re-initialization from EEPROM by sending a specific command to the serial interface. Parity is checked continuously during every read from RAM. If incorrect data is detected, the Diagnostic Mode is activated (an error code is written to the serial digital output, and the analog output is set to the diagnostic level). * I2C™ is a trademark of NXP. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 5 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 1.3 General Working Modes ZSSC313x supports three different working modes: Normal Operation Mode (NOM) Command Mode (CM) Diagnostic Mode (DM) 1.3.1 Normal Operation Mode (NOM) The Normal Operation Mode (NOM) is the recommended working mode for applications. After power-on, the ZSSC313x completes an initialization routine during which the EEPROM is mirrored to RAM and the contents are checked against a stored signature. If enabled, a ROM signature check is processed (ZSSC3136 only). If any error is detected, the Diagnostic Mode is activated. Otherwise the configuration of the ZSSC313x is set, the serial digital interfaces are enabled, and NOM is started. In NOM, the continuous measurement cycle and conditioning calculations are processed. The signal conditioning results generate the analog output at pin AOUT. Provided that the EEPROM is programmed correctly, NOM works without sending any command to the digital serial interface. Readout of the conditioning results via the 2 digital serial interface (I C™ or OWI) is possible. This does not interrupt the continuous processing of the signal conditioning routine. After power-on, a startup window is opened for one-wire communication (OWI) via the AOUT pin. During the startup window, the output level at pin AOUT depends on the selected OWI mode (see section 3.4). To activate the Command Mode (CM) for end-of-line configuration and calibration, send the START_CM command via OWI communication during the startup window (refer to the data sheet for timing specifications for the startup window). In CM, NOM is stopped and the ZSSC313x waits for further commands. The ZSSC313x provides the analog voltage output of the bridge sensor signal at the AOUT pin. For the compensation of temperature dependent deviations by conditioning calculations, a calibration temperature is measured. The measurement cycle is fixed. It includes the measurement of the main signals and the safety tasks as shown in Figure 1.1. All measured signals are auto-zero compensated to eliminate offsets resulting from the selected measurement channel. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 6 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Figure 1.1 Measurement Cycle CTAZ CT Measurement Cycle with Bridge Signal Output BRAZ CFGAPP:BRCNT = 0 Startup BR (1 Bridge Sensor Signal measurement per special measurement) CTAZ BR CT BR CMV BR SSCP BR SSCN BR BRAZ 12 Measurements per Cycle Measurement Cycle CTAZ CT Measurement Cycle with Bridge Signal Output BRAZ CFGAPP:BRCNT = 1 Startup (30 Bridge Sensor Signal measurements per special measurement) BR BR ... BR CTAZ BR BR ... BR CT 62 Measurements per Cycle BR BR ... BR CMV BR BR ... BR SSCP 62 Measurements per Cycle BR BR ... BR SSCN BR BR ... BR BRAZ 62 Measurements per Cycle 186 Measurements per Cycle Measurement Cycle Measurement Cycle Phases Main Signals Measurement BR Safety Functions Measurement * Bridge Sensor Measurement BRAZ Bridge Sensor Auto-Zero Measurement 1.3.2 Calibration Temperature Measurement SSCP Sensor Short Check CTAZ Calibration Temperature SSCN Sensor Short Check CT Auto-Zero Measurement Positive-Biased Measurement Negative-Biased Measurement Analog Output Updated CMV Sensor Common Mode Voltage Measurement Bridge Sensor Signal * Not available for all ZSSC313x products. See Table 1.1. Command Mode (CM) The Command Mode (CM) is the working mode that is used for calibration data acquisition and access to the internal RAM and EEPROM of the ZSSC313x. The CM start command START_CM aborts the running NOM, so the measurement cycle stops. The ZSSC313x changes to CM only after receiving the START_CM command by 2 digital serial communication (I C™ or OWI). This protects the ZSSC313x against interruption of processing the NOM (continuous signal conditioning mode) and/or unintentional changes of configuration. In CM, the full set of commands is supported (see section 4.1). Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 7 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 2 Starting CM via I C™ communication (SCL and SDA pins) is possible at any time. If starting CM via one-wire communication (AOUT pin), the START_CM command must be transmitted when OWI is enabled, i.e. during the OWI startup window or during permanent OWI output mode (see section 3.4.2 for OWI configuration). If the ZSSC313x receives a command other than START_CM in NOM, it is not valid. It is ignored and no interrupt to the continuous measurement cycle is generated. Refer to section 4.4.1 for a detailed description of the START_CM command. In CM, the full command set is enabled for processing. During processing of a received command, the digital serial interfaces are disabled; no further commands are recognized. After finishing the processing, the CMC waits for further commands or processes requested measurement loops continuously. EEPROM programming is only enabled after receiving the EEP_WRITE_EN command. Figure 1.2 Modes of Digital Serial Communication Normal Operation Mode 2 I C™ à Read only 1.3.3 Command Mode Command START_CM 2 I C™ or OWI à Full command set Diagnostic Mode (DM) The ZSSC313x detects various failures. When a failure is detected, Diagnostic Mode (DM) is activated. DM is indicated by setting the output pin AOUT to the Lower Diagnostic Range (LDR). When using digital serial 2 communication protocols (I C™ or OWI) to read out conditioning results data, the error status is indicated by a specific error code. OWI communication is enabled during DM. Because the analog output pin AOUT is driven to the diagnostic range, the AOUT pin must be overwritten when starting OWI communication. The communication master must provide driving capability (AOUT current limitation: <20mA). Note that many of the error detection features can be enabled or disabled by configuration words CFGAPP and CFGSF (see section 5.3). There are three possible conditions for Diagnostic Mode determined by the type of error (see Table 1.1): Steady Diagnostic Mode In steady DM, the measurement cycle is stopped and failure notification is activated. If enabled by the configuration bit ADJREF:DMRES, a reset after the time-out of a watchdog is executed. Temporary Diagnostic Mode There is a failure counting sequence that can result in a temporary DM. DM is activated after two consecutively detected failure events and is deactivated after a failure counter counts down if the failure condition is no longer detected. The measurement cycle is continuously processed during temporary DM. Power and Ground Loss Power and ground loss cases are signaled by setting the analog output pins to high-impedance states. The output levels are determined by the external loads. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 8 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 1.3.4 Failsafe Tasks and Error Codes Table 1.1 Error Detection Functionality and Error Codes Failsafe Task Description Messaging Time Oscillator Fail Detection Oscillator is observed generating clock pulses by an asynchronous timing logic < 200µs Watchdog Watchdog time-out during initialization or measurement cycle Register Parity Error Code1) Activation - Startup, two measurement times C008HEX - Hard-wired parity check of configuration registers Immediately C002HEX - RAM Parity Parity check at every RAM access Immediately C001HEX - EEPROM Multiple-Bit Error Detection of non-correctable multiple-bit error per 16-bit word Startup C004HEX - EEPROM Signature Checks signature of RAM mirror against signature stored in EEPROM Startup C0AAHEX - ROM Signature Checks CMC ROM signature Note that this check increases startup time by 10ms. Startup C0CCHEX CFGAPP: CHKROM Arithmetic Check Functional check of arithmetic unit - Data Bus Check Functional check of internal peripheral data bus - MCCH Main channel check – High: Detection of positive overdriving the analog front-end during bridge measurement CFGSF: CHKMCCH MCCL Main channel check – Low: Detection of negative overdriving the analog front-end during bridge measurement ZSSC3135/36/38 ZSSC3136 only - Two measurement cycles C010HEX CFGSF: CHKMCCL SAC Bridge sensor aging check CMVMIN / CMVMAX TSC Temperature sensor check CFGAPP: CHKTS SCC Bridge sensor connection check CFGAPP: CHKSENS Bridge sensor short check CFGAPP: CHKSENS, CFGSF: SSCDIS SSC Power & Ground Loss Power and ground loss detection 1) < 5ms - - Action Temporary DM Steady DM or reset after watchdog time-out (if enabled by ADJREF: DMRES) Steady DM Temporary DM Reset Error codes can be bitwise OR-combined. Note that the reset after the watchdog time-out clears any error codes that were previously generated. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 9 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 1.3.4.1 Main Channel Check (MCCH / MCCL) available in ZSSC3136 The main channel check detects whether the ADC dynamic range has been exceeded during the bridge measurement. The bridge signal raw value is checked if it is less than 128 or greater than (2 is the selected ADC resolution. 16/15-bit values are shifted to 14/13-bit before the check. rADC - 128) where rADC This can result from various causes: the bridge sensor is disconnected; the main input channel is defective or not sufficiently calibrated; or the bridge signal is out of targeted range. The main channel check distinguishes between positive (MCCH) and negative (MCCL) overdrive to allow tailored overdrive handling at the bridge channel. 1.3.4.2 Bridge Sensor Aging Check (SAC) available in ZSSC3136 The sensor aging check detects long-term altering of the bridge sensor resistors that would result in a shift of the calibrated output characteristics. The SAC evaluates the common mode voltage of the sensor bridge once per measurement cycle if enabled. The measurement result is checked for compliance with programmed limits (CMVMIN / CMVMAX). 1.3.4.3 Temperature Sensor Check (TSC) available in ZSSC3135, ZSSC3136 and ZSSC3138 The temperature sensor check detects whether the ADC dynamic range has been exceeded during the temperature measurement. The temperature signal raw value is checked if it is less than 128 or greater than rADC (2 - 128) where rADC is the selected ADC resolution. 16/15-bit values are shifted to 14/13-bit before check. This can result from various causes: the external temperature sensor is disconnected; the analog temperature input channel is not sufficiently calibrated or defective; or the temperature signal is out of targeted range. 1.3.4.4 Bridge Sensor Connection Check (SCC) available in the ZSSC3135, ZSSC3136 and ZSSC3138 The sensor-connection check monitors the connection of the bridge sensor at the VBP and VBN pins. An internally determined current is applied to the sensor, and the resulting differential input signal is evaluated once per measurement cycle if enabled. The following failures are detected by SCC: High-resistive sensor bridge elements (e.g., a diaphragm rapture) Connection loss at the pins VBP, VBN, VBR_T, or VBR_B Short between pins VBP or VBN and pins VBR_T or VBR_B 1.3.4.5 Bridge Sensor Short Check (SSC) available in ZSSC3135, ZSSC3136 and ZSSC3138 The sensor-short check detects a short between the bridge sensor input pins VBP and VBN (connections less than 50Ω nominal). An internally determined current is applied to the sensor in both directions, resulting in differential input signals that are evaluated once per measurement cycle if enabled. If a short occurs, the input signal difference of both is less than an internally determined limit. Increasing the sensor-short check limit via CFGAPP:CHKSSCL is recommended in the case of a sensor bridge with low impedance (less than 2kΩ). 1.3.4.6 Power and Ground Loss Detection of a power or ground loss is indicated by pulling the analog output AOUT to the diagnostic range. The level of the diagnostic output depends on the lost node and load connection to ground or supply. In such cases, the ZSSC313x is inactive and the specified leakage current in combination with the load resistor guarantees reaching the Upper Dignostic Range (UDR) or the Lower Diagnostic Range (LDR). Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 10 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 2 Signal Conditioning 2.1 A/D Conversion During NOM, the analog preconditioned sensor signal is continuously converted from analog to digital. The analog-to-digital (A/D) conversion is performed with the selected resolution rADC, which is equal for all measurements in the measurement cycle (e.g., bridge sensor signal, calibration temperature, auto-zero, etc.). The A/D conversion is configurable regarding the inherent range shift rs ADC for the bridge sensor signal measurement. One or two step A/D conversion mode is selectable; the two-step mode is faster, the one-step mode is more accurate because of its longer integration time. All resulting digital raw values are determined by the following equations: Analog differential input voltage to A/D conversion VADC_DIFF aIN VIN_DIFF a XZC VXZC (1) Where VADC_DIFF Differential input voltage to ADC aIN Gain of analog front-end for differential input voltage VIN_DIFF Differential input voltage to analog front-end. Extended Zero Compensation (ZSSC3138 only): aXZC Gain of extended zero compensation voltage VXZC Extended zero compensation voltage = -(-1 ) * VADC_REF * BRXZC / 48 using CFGAFE:BRXZC and CFGAFE:BRXZCPOL (see section 5.3); see below for VADC_REF. BRXZCPOL Digital raw A/D conversion result ZADC VADC_DIFF VOFF ZADC 2rADC rs ADC VADC_REF (2) Where rADC Resolution of A/D conversion (ZSSC3131/35/36: 13, 14 bit; ZSSC3138: 13, 14, 15, 16 bit) VOFF Residual offset voltage of analog front-end (which is eliminated by auto-zero compensation) VADC_REF ADC reference voltage (ratiometric reference for measurement) rsADC Range shift of A/D conversion (bridge sensor: ½, ¼, /8, /16; Temperature: ½) 1 1 Auto-zero value ZAZ VOFF Z AZ 2rADC rs ADC VADC_REF Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. (3) 11 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Auto-zero corrected raw A/D conversion result ZCORR Z CORR Z ADC Z AZ 2rADC 2.2 VADC_DIFF (4) VADC_REF Digital Value Range Zooming (ZSSC3138 only) The digital zooming feature is available for the ZSSC3138 only. The result of the A/D conversion ZCORR, which is the input value for the signal conditioning formula, depends on the resolution setting rADC ranging from 13 to 16 bit resolution. Raw values acquired with resolutions of 15 and 16 bits must be mapped to the 13 or 14 bit resolution range for further calculations. This is done by different methods depending on the data to be measured: SSC+ and SSC- measurements for diagnostic checks are always shifted to 13 bits. The temperature measurement value (ZCORR_T) is divided by 4. 15 The bridge sensor (BR) measurement auto-zero corrected data (ZCORR) must be moved in the +/- 2 range (see Table 2.1) by subtraction of the offset determined in configuration register CFGAPP:BROFFS (see Table 5.4). Minimum and maximum input data (span of ZCORR raw data) should have 14-bit or slightly higher resolution (16384 ADC counts) for proper calibration coefficients calculation. AD conversion result segmentation calculation (only if r ADC = 15 or 16 bit) ZCORR_OUT ZCORR BROFFS 213 with BROFFS [0; 7] (5) Where ZCORR Raw input main channel A/D result for measured value (auto-zero compensated; D8HEX and D9HEX commands) ZCORR_OUT Raw main channel A/D result for measured value (auto-zero compensated), mapped in range given in Table 2.1 ZCORR_TOUT ZCORR_T (6) 4 Where ZCORR_T Raw temperature input A/D result for measured value (auto-zero compensated) ZCORR_TOUT Raw temperature A/D result for measured value (auto-zero compensated), mapped in range [-2 ; 2 ) 14 14 Note: All raw data acquiring commands (Dx commands listed in Table 4.1) do not process the shifting procedure, and therefore 15 and 16 bit results are read out. Therefore, the acquired data must be processed according to the ZCORR_OUT and ZCORR_TOUT formulas above in the following sequence before calculation of the calibration coefficients: 1. Raw calibration data acquisition 2. ZCORR_OUT calculation for the main channel data and the ZCORR_T calculation for temperature data 3. Calibration coefficients calculation using calculated corrected raw data Important: Results of the ADC conversion ZCORR_OUT greater than +32767 counts (15 bits) will result in negative read-out values and a wrong analog output voltage for AOUT. In this case, a greater offset BROFFS, adjusted ADC Range Shift, or lower gain should be used. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 12 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Table 2.1 Valid Data Ranges for 15-bit and 16-bit ADC Resolution ADC Range Shift ADC Resolution 16 bits 15 bits Data ZCORR (D8HEX and D9HEX commands) 16 bits 15 bits ZCORR_OUT 1/2 3/4 7/8 15/16 Min Max Min Max Min Max Min Max -32768 32767 -16384 49151 -8192 57343 -4096 61439 -16384 16383 -8192 24575 -4096 28671 -2048 30719 -32768 32767 -16384 32767 -8192 32767 -4096 32767 -16384 16383 -8192 24575 -4096 28671 -2048 30719 Recommendation: To avoid possible ADC saturation, perform a check on the ADC raw data (D0 HEX and D1HEX res commands). For results close to the limits [0-2 ), a lower gain or adjusted ADC Range Shift should be used. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 13 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 2.3 Signal Conditioning Formula The digital raw value ZCORR for the measured bridge sensor signal is processed with a conditioning formula to rd remove offset and temperature dependency and to compensate nonlinearity up to the 3 order. The signal conditioning equation is processed by the CMC and is defined as follows: Range definition of inputs Z CORR 2rADC ; 2rADC (7) Z CORR_T 2rADC 1; 2rADC 1 (8) Where ZCORR Raw A/D conversion result for bridge sensor signal (auto-zero compensated) rADC Resolution of A/D conversion (13 or 14 bit) ZCORR_T Raw A/D conversion result for calibration temperature (auto-zero compensated) Conditioning Equations 2 Z CORR c 0 2 (rADC 1) c 4 Z CORR_T 2 2(rADC 1) c 5 Z CORR_T Y 0; 1 (9) S Y 1 215 c 2 215 c 3 215 c 2 Y 2 215 c 3 Y3 S 0; 1 (10) Y 2 c1 2 (rADC 1) c 6 Z CORR_T 2 2(rADC 1) c 7 Z CORR_T Where Conditioning coefficients stored in EEPROM registers 0 to 7: c i [-2 ; 2 ), two’s complement. 15 c0 Bridge offset c1 Bridge gain c2 Non-linearity correction 2 nd order rd c3 Non-linearity correction 3 order c4 Temperature coefficient for bridge offset 1 order c5 Temperature coefficient for bridge offset 2 st Temperature coefficient for gain 1 order c7 Temperature coefficient for gain 2 September 1, 2015 nd order st c6 Functional Description 15 nd order © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 14 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family The first equation compensates the offset and fits the gain including its temperature dependence. The nonlinearity is then corrected for the intermediate result Y. The result of these equations is a non-negative value S for measured bridge sensor signal in the range [0; 1). Note that the conditioning coefficients ci are positive or negative values in two’s complement. 2.4 Fitting Conditioning Result to Analog or Digital Output The analog output is generated by a 5632-step D/A converter. This guarantees 12-bit analog output resolution for a typical output range of 10-to-90% VDDA or larger. For the calibration of the conditioning coefficients, the target output values must be fitted to that DAC resolution. The fitting factor is 0.6875 = 5632 13 and is applied to the normalized target values S [0; 1). 2 Note that this fitting is supported by the ZSSC313x calibration software, but fitting is not included in RBIC1.DLL. Refer to ZSSC313x Technical Note – Calibration DLL Description for stand-alone usage of the DLL. The conditioned 15-bit value S is continuously written to the output register of the digital serial interface during the 2 2 measurement cycle and can be readout via I C™ or OWI communication. Note, if only digital ouput via I C™ or OWI is used, fitting S to the DAC range is not advisable. Instead the full 15-bit resolution/accuracy should be used. 2.5 Digital Filter Function The ZSSC313x offers a digital (averaging) low-pass filter for the analog output signal at the AOUT pin. The output value is filtered with the integrating coefficient LPFAVRG and the differential coefficient LPFDIFF (refer to section 5.2). Note that setting the coefficients LPFAVRG and LPFDIFF to 0 disables the filter function. The filter function is implemented as follows: Digital Filter Function S OUT,0 S 0 S OUT,i S OUT,i-1 S i S OUT,i1 LPFDIFF 1 2LPFAVRG (11) i>0; S OUT,i 0;1 (12) with LPFAVRG, LPFDIFF [0; 7] Where Si Conditioned output value (see section 2.3) SOUT,I Filtered output value LPFAVRG Low-pass filter coefficient stored in EEPROM: averaging filter coefficient LPFDIFF Low-pass filter coefficient stored in EEPROM: differential filter coefficient The result of the filter function is a non-negative value SOUT,i in the range [0; 1), which is used for continuously updating the analog output value during the measurement cycle. Important: For proper function, ensure that the factor Functional Description September 1, 2015 LPFDIFF 1 never becomes larger than 1. 2LPFAVRG © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 15 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 2.6 Analog Output Signal Range and Limitation The filtered conditioning result SOUT for the measured bridge signal is output at the analog output pin AOUT with a resolution greater than 12 bits. The analog output voltage is generated using a resistor-string DAC with 5632 steps, of which 5120 steps (256 to 5375) can be addressed. Consequently an adjustable range from 5% to 95% of the supply voltage is guaranteed, including all possible tolerances. VOUT_MIN VVDDE VVSSE VOUT_MAX VVDDE VVSSE 256 5632 5375 5632 (13) Setting the analog output outside the allowed range (for example via the SET_DAC command) will result in entering the diagnostic mode (DM) and setting the output to the LDR (Lower Diagnostic Range). Note that the limit setting registers 8 and 9 are shared with the digital filter configuration (the 3 LSBs). Figure 2.1 Accessable Output Signal Range and Limitation Adressable Range SOUT, SAOUT Functional Description September 1, 2015 5631 5375 Limmax Limmin 256 0 smin smax Bridge Sensor Signal © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 16 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family The ZSSC313x offers an output limitation function for the analog output SOUT which clips the output signal with the configurable limits AOUTMIN and AOUTMAX (refer to section 5.2). Analog Output Limitation S AOUT SOUT AOUTMAX AOUTMAX (14) S AOUT SOUT AOUTMIN; AOUTMAX SOUT (15) S AOUT SOUT AOUTMIN AOUTMIN AOUTMIN, AOUTMAX 256; 5375 100HEX ; 14FFHEX (16) Where SOUT Conditioned and filtered output value (see section 2.3 and 2.5) SAOUT Clipped analog output value AOUTMIN Analog output limit stored in EEPROM: lower analog output limit AOUTMAX Analog output limit stored in EEPROM: upper analog output limit The analog output voltage VAOUT is ratiometric to the power supply and can be calculated using equation (17): VAOUT VVDDE VVSSE S AOUT 5632 (17) Where SAOUT Conditioned, filtered and clipped output value VAOUT Analog output voltage VVDDE, VVSSE Potential at VDDE and VSSE pins 2 Note that the readout of measured values in NOM via I C™ or OWI delivers conditioned but unfiltered and unclipped values for S. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 17 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 3 Serial Digital Interfaces 3.1 General Description 2 TM The ZSSC313x includes a serial digital I C™ interface and a ZACwire interface for one-wire communication (OWI). The digital interfaces allow programming the EEPROM to configure the application mode for the ZSSC313x and to calibrate the conditioning equations. It also provides the readout of the conditioning results as a digital value. The ZSSC313x always works as a slave. 2 I C™ access to the ZSSC313x is available in all operation modes independent of the programmed configuration. 2 The I C™ interface is enabled after power-on and a short initialization phase. In Normal Operation Mode (NOM), the result values for the bridge sensor signal can be read out. For OWI communication, there are four possible access modes during NOM selectable by the ADJREF:IFOWIM bits. A mode with continuous OWI access and two startup window modes are available. The startup window modes differ in the analog output behavior: with simultaneous analog output or without analog output. The fourth 2 option is to lock OWI access; in this case, communication is only available via I C™. Transmitting the command START_CM enables the Command Mode (CM). In CM, either communication protocol 2 can be used; all commands are available to process calibration. EEPROM write access via I C™ is always available in CM. The EEPROM lock bit only affects EEPROM write access via OWI communication (see section 3.4.2). In Diagnostic Mode (DM), both communication protocols can be used to read an error code to identify the error source. A non-configured device, identified by a non-consistent EEPROM signature, starts up in DM. Because the analog output pin AOUT is driven to the lower diagnostic range in DM, the analog output must be overwritten when starting communication using OWI communication. Starting CM from DM by transmitting the START_CM 2 command is possible by using I C™ or OWI communication. In NOM, CM, and DM, an alternating use of communication protocols is permitted. 3.1.1 Command Structure A command consists of a device address byte and a command byte. Some commands (e.g. writing data into EEPROM) also include two data bytes. The command structure is independent from the communication protocol used. Refer to section 1.3 for details of working modes and section 4 for command descriptions. 3.1.2 Addressing 2 Addressing is supported by I C™ and OWI communication protocol. Every slave connected to the master responds to a defined address. After generating the start condition, the master sends the address byte containing a 7-bit address followed by a data direction bit (R/W). ”0” indicates a transmission from master to slave (WRITE); 2 “1” indicates a data request (READ). The addressed slave answers with an acknowledge bit (I C™ only). All other slaves connected to the master ignore this communication. The ZSSC313x always responds to its general ZSSC313x slave address, which is 78 HEX (7bit). Via EEPROM programming, it is possible to allocate and activate an additional unique slave address within the range 70 HEX to 7FHEX to the ZSSC313x. In this case, the device recognizes communication on both addresses, on the general one and on the additional one. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 18 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 3.1.3 Read-Request There are two general methods/requests for reading data from the ZSSC313x: Digital read out 2 (Continuously) reading the conditioned result in NOM via I C™ or via OWI communication During the measurement cycle, the ZSSC313x transfers the conditioned result for bridge sensor signal into the output registers of the digital interfaces. These data will be sent if a master generates a read-request via I2C™ or via OWI. The active measurement cycle is not interrupted by this. 2 Calibration and/or configuration tasks via I C™ or via OWI communication Reading internal data (e.g. EEPROM content) or acquired measurement data in CM To read internal and/or measurement data from the ZSSC313x in CM, usually a specific command must be sent to transfer this data into the output registers of the digital interfaces. Thereafter the data will be sent if the master generates a read-request. 3.1.4 Communication Verification In Normal Operation Mode (NOM) and in Command Mode (CM), a read request is answered by return of the data present in the digital interface output registers (2 bytes). Next a check sum is sent (1 byte) followed by the command which is answered (see section 3.2). The check sum and the returned command allow the verification of received data by the master. For details and exceptions, also see section 4.3. 3.1.5 Communication Protocol Selection 2 Both available protocols, I C™ and OWI, can be active simultaneously, but only one interface can be used at a time. An OWI communication access is also possible if OWI communication is enabled and analog output is active at the same time (i.e., during the startup window, in Diagnostic Mode, or in Command Mode after START_CYCx commands). For this, the active output AOUT must be overwritten by the communication master, so generating a stop condition before starting the communication is recommended to guarantee a defined start of communication (refer to Figure 3.9). Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 19 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 3.2 Digital Output A read request is answered by transmitting data from the digital interface output registers. 2 During the continuous measurement cycle (NOM), digital output via the I C™ interface sends the 15-bit bridge sensor value. The MSB carries the diagnostic status (ERR). Data validation is available by reading an additional check sum byte. The data is updated continuously when a new conditioned value is calculated. 2 Figure 3.1 I C™ Read Request during Normal Operation Mode Device Address Bridge Sensor Signal High Byte Address Value 78HEX Low Byte Bridge sensor signal (conditioned 15-bit value) R/W ERR Byte Validation 1 0 MSB High Byte Low Byte check sum 00HEX LSB MSB LSB MSB LSB During Diagnostic Mode (DM, see section 1.3.3), the diagnostic status bit (ERR) is set to “1.” An error code is also transmitted to identify the failure source. 2 Figure 3.2 I C™ or OWI Read Request in Diagnostic Mode Device Address Bridge Sensor Signal High Byte Address Value 78HEX R/W ERR Byte Validation Low Byte Error Code 1 1 MSB High Byte Low Byte check sum 00HEX LSB MSB LSB MSB LSB In Command Mode (CM) a 2-byte answer is generated for every received command. A 1-byte check sum is added followed by the command that is being answered. The check sum and the command echo allow verification of received data by the master. For details and exceptions, see section 4.3. 2 Figure 3.3 I C™ or OWI Read Request Answering a Command (CM) Device Address Answer High Byte Address Value Functional Description September 1, 2015 78HEX R/W Byte 1 MSB Validation Low Byte Response (2 bytes) LSB MSB High Byte Low Byte check sum Command Echo LSB MSB © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. LSB 20 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family I2C™ Protocol 3.3 2 For I C™ communication, a data line (SDA) and a clock line (SCL) are required. 2 Figure 3.4 Principles of I C™ Protocol SCL SDA start condition valid data proper change of data stop condition 2 The I C™ communication and protocol used are defined as follows: Idle Period When the bus is inactive, SDA and SCL are pulled-up to supply voltage VVDDA. Start Condition A high-to-low transition on SDA while SCL is at the high level indicates a start condition. Every command must be initiated by a start condition sent by a master. A master can always generate a start condition. Stop Condition A low-to-high transition on SDA while SCL is at the high level indicates a stop condition. A command must be closed by a stop condition to start processing the ZSSC313x internal command routine. The ZSSC313x changes to inactive interface mode during processing. Valid Data Data is transmitted in bytes (8 bits) starting with the most significant bit (MSB). Each byte transmitted is followed by an acknowledge bit. Transmitted bits are valid if after a start condition, SDA maintains a constant level during a high period of SCL. The SDA level must change only when the clock signal at SCL is low. Acknowledge An acknowledge bit after a transmitted byte is required. The master must generate an acknowledge-related clock pulse. The receiver (slave or master) pulls-down the SDA line during the acknowledge clock pulse. If no acknowledge is generated by the receiver, a transmitting slave will remain inactive. A transmitting master can abort the transmission by generating a stop condition and can then repeat the command. A receiving master must signal the end of transfer to the transmitting slave by not generating an acknowledge bit and afterwards transmitting a stop condition. Write Operation During transmission from master to slave (WRITE), the device address byte is followed by a command byte and, depending on the transmitted command, up to 2 optional data bytes. The internal microcontroller evaluates the received command and processes the related routine. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 21 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 2 Figure 3.5 I C™ Write Operation I2C WRITE, 1 Command Byte, 2 Data Bytes: optional S 6 5 4 3 2 1 0 W A 7 6 5 4 3 2 1 0 A 15 14 13 12 11 10 9 8 A 7 6 5 4 3 2 1 0 A S Device Slave Address [6:0] Command Byte [7:0] Data [15:8] Data [7:0] Wait for Slave ACK I2C WRITE, 1 Command Byte, no Data: Wait for Slave ACK S 6 5 4 3 2 1 0 W A 7 6 5 4 3 2 1 0 A S Device Slave Address [6:0] Command Byte [7:0] Wait for Slave ACK S Start Condition S Stop Condition 5 Device Slave Address (example: Bit 5) W Write Bit (Write = 0) Wait for Slave ACK A Acknowledge (ACK) 2 Data Bit (example: Bit 2) Read Operation After a data request from master to slave by sending a device address byte including a set-data-direction bit, the slave answers by sending data from the interface output registers. The master must generate the transmission clock on SCL, acknowledges after each data byte (except after the last one), and then the stop condition. A data request is answered by the interface module itself and consequently does not interrupt the current process of the internal microcontroller. The data in the output registers is sent continuously until a missed acknowledge occurs or a stop condition is detected. After transmitting all available data, the slave starts repeating the data. During normal operation, measurement cycle data is continuously updated with conditioning results. To get other data from the slave (e.g., EEPROM content) a specific command must be sent before the data request to initiate the transfer of this data to the interface output registers. This command does interrupt the current process of the internal microcontroller, e.g. the active measurement cycle. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 22 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 2 Figure 3.6 I C™ Read Operation (Data Request) I2C Read, 2 (+n) Data Bytes: optional S 6 5 4 3 2 1 0 R A 15 14 13 12 11 10 9 8 A 7 6 5 4 3 2 1 0 A 7 6 5 4 3 2 1 0 N S Device Slave Address [6:0] Data [15:8] Wait for Slave ACK S Start Condition 5 Master ACK S Stop Condition Device Slave Address (example: Bit 5) 2 … nth Byte Data [7:0] A Acknowledge (ACK) Master ACK N Master ACK No Acknowledge (NACK) R Write Bit (Read = 1) Data Bit (example: Bit 2) 2 Figure 3.7 Timing I C™ Protocol SDA tI2C_SU_DAT tI2C_L tI2C_BF SCL tI2C_HD_STA Table 3.1 tI2C_HD_DAT tI2C_H tI2C_SU_STA tI2C_R tI2C_F tI2C_SU_STO 2 Timing I C™ Protocol Nr. Parameter Symbol 1 SCL clock frequency fSCL 2 Bus free time between start and stop condition tI2C_BF 1.3 s 3 Hold time start condition tI2C_HD_STA 0.6 s 4 Setup time repeated start condition tI2C_SU_STA 0.6 s 5 Low period SCL/SDA tI2C_L 1.3 s 6 High period SCL/SDA tI2C_H 0.6 s 7 Data hold time tI2C_HD_DAT 0 s 8 Data setup time tI2C_SU_DAT 0.1 s 9 Rise time SCL/SDA tI2C_R 0.3 s 10 Fall time SCL/SDA tI2C_F 0.3 s 11 Setup time stop condition tI2C_SU_STO 12 Noise interception SDA/SCL tI2C_NI Functional Description September 1, 2015 min typ Max Unit Conditions 400 kHz fOSC ≥ 2MHz s 0.6 50 ns Spike suppression © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 23 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 3.4 One-Wire Communication (OWI) TM The ZSSC313x utilizes ZMDI’s ZACwire interface, a digital interface concept for one-wire communication (OWI). It combines a simple and easy protocol adaptation with cost-saving pin sharing. The OWI communication 2 2 principle is derived from the I C™ protocol, so becoming familiar with the I C™ protocol is recommended for an understanding of OWI communication. Both the analog voltage output for normal operation and the one-wire digital interface for calibration use the same pin AOUT. This enables “end of line” calibration; no additional pins are required to digitally calibrate a finished assembly. 3.4.1 Properties and Parameters The ZSSC313x works as an OWI slave. An external master must control the communication by transmitting commands or data requests. Figure 3.8 explains the physical OWI connection in principle. Note that pulling up the OWI connection line must be done externally. There is no guarantee for using the ZSSC313x internal pull-up. In addition, it might be necessary to implement a master push-pull driver to overwrite an analog output voltage at pin AOUT (IOUT,max = 20mA). OWI communication is self-locking (synchronizing) on the master’s communication speed in the range of the defined OWI bit time, which is guaranteed for the ZSSC313x’s clock frequency in the range of 2 to 4MHz. Table 3.2 OWI Interface Parameters Nr. Parameter 1 OWI bit time 2 Pull-up resistance master 3 Symbol Unit Conditions tOWI,BIT 0.04 to 4 ms ROWI,PULLUP 3.3 (typical) k OWI line resistance ROWI,LINE <0.01 ROWI,PULLUP 4 OWI load capacitance COWI,LINE 50 (typical) nF 5 Voltage level LOW VOWI,LOW 0.2 VDDA Min VDDA is 4.2V @ 4.5V VDDE 6 Voltage level HIGH VOWI,HIGH 0.75 VDDA Max VDDA is 5.5V @ 5.5V VDDE Functional Description September 1, 2015 tOWI,BIT = 5 * ROWI,PULLUP * COWI,LINE Guaranteed for fOSC = 2 to 4MHz Total OWI line load © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 24 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Figure 3.8 Block Schematic of an OWI Connection ZSSC313x External Master Slave 5µA ROWI,PULLUP ROWI_PUP OWI Connection ROWI,LINE COWI,LINE 3.4.2 OWI Communication Access OWI communication must be started when the ZSSC313x is enabled for reception. This depends on the configured OWI mode ADJREF:IFOWIM (see section 5.2). There are two OWI modes available with a startup window (nominal 52700 internal frequency clocks) after power-on and one continuous OWI communication mode. There is also a selectable mode in which OWI communication is completely disabled. OWI communication continuously enabled (OWIENA) OWI access remains always active at AOUT pin; the analog output is disabled. In Normal Operation Mode (NOM) the bridge sensor signal output can be readout with a cyclic read request. Command Mode (CM) can always be started by sending the command START_CM. OWI startup window (OWIWIN) OWI access is enabled during the startup window. The OWI master must send the START_CM command during the startup window to interrupt the start of analog output and to switch to CM. Analog voltage output starts if the startup window expires without receiving a valid START_CM command, and therefore OWI access is disabled. A cyclic readout of bridge sensor signal via OWI in NOM is not available. OWI startup window with analog voltage output (OWIANA) OWI access is enabled during the startup window. The analog voltage output starts immediately after power-on (maximum 5ms) simultaneously with the OWI startup window. For switching to CM, the OWI master must overwrite the active analog voltage output to send the START_CM command. This also ends the analog voltage output. OWI access is disabled if the startup window expires without receiving a valid START_CM command. A cyclic readout of the bridge sensor signal via OWI in NOM is not available. OWI communication disabled (OWIDIS) 2 OWI access is not possible. In this mode, access to ZSSC313x is only available via the I C™ interface. In Command Mode (CM), OWI communication is always possible. After certain commands requesting an analog output at the AOUT pin, the OWI master must overwrite the analog voltage output for further communication. In Diagnostic Mode (DM), OWI communication is also possible. If the AOUT pin is driven to the Lower Diagnostic Range (LDR), again the OWI master must overwrite this voltage level for communication. Note that an unconfigured ZSSC313x with an invalid EEPROM signature always starts in DM. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 25 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 3.4.3 OWI Protocol OWI communication is always initiated by a master. Transmission starts with an address byte including a read/write bit to define the direction of the following byte transfer. The OWI protocol is defined as follows: Idle Period During inactivity of the bus, the OWI communication line is pulled-up to supply voltage VVDDE by an external resistor. Start Condition * When the OWI communication line is in idle mode, a low pulse with a minimum width of 10µs and then a return to high indicates a start condition. Every command must be initiated by a start condition sent by a master. A master can generate a start condition only when the OWI line is in idle mode. Stop Condition A constant level at the OWI line (no transition from low to high or from high to low) for at least twice the period of the last transmitted valid bit indicates a stop condition. Without considering the last bit-time (secure stop condition), a stop condition is generated with a constant level at the OWI line for at least 20ms. The master finishes a transmission by changing back to the high level (idle mode). Every command (see the subsequent “Write Operation” section) must be closed by a stop condition to start processing the command. The master must interrupt a sending slave after a data request (see the subsequent “Read Operation” section) by clamping the OWI line to the low level for generating a stop condition. In the case of an active analog voltage output at the AOUT pin, the output level must be overwritten by the OWI master. For example, this can occur if the OWI communication is started in the OWI startup window with a simultaneous analog voltage output. To ensure correct communication, first generate a stop condition (see Figure 3.9) before sending the first command (e.g., START_CM). After the ZSSC313x receives this first command, the analog output is disabled and OWI communication functions without sending additional sequences further on. Figure 3.9 Example of OWI and Actively Driven AOUT – Starting OWI Communication with a Stop Condition AOUT1 one bit time = 100µs * one bit time = 100µs one bit time = 100µs stop condition = 300µs (longer than two bit times) start cond. = 100µs 1st bit of data (LOW or HIGH) 2nd bit Valid Data Data is transmitted in bytes (8 bits) starting with the most significant bit (MSB). Transmitted bits are recognized after a start condition at every transition from low to high at the OWI line. The value of the transmitted bit depends on the duty ratio between the high phase and high/low period (bit period tOWI,BIT in Figure 3.12). A duty ratio greater than 1/8 and less than 3/8 is detected as “0”; a duty ratio greater than 5/8 and less than 7/8 is detected as “1.” The bit period of consecutive bits must not change by more than a factor of 2 because the stop condition is detected in this case. 10µs is the minimum tOWI,STA that guarantees the OWI start condition in the range fOSC = 2 to 4MHz. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 26 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Write Operation During transmission from master to slave (WRITE), the address byte is followed by a command byte and, depending on the transmitted command, by an optional 2 data bytes. The internal microcontroller evaluates the received command and processes the requested routine. Figure 3.10 illustrates the writing of a command with two data bytes and without data bytes. See section 4.1 for details of the command set. Figure 3.10 OWI Write Operation optional OWI WRITE, 1 Command Byte, 2 Data Bytes: S 6 5 4 3 2 1 0 W 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 S Device Slave Address [6:0] Command Byte [7:0] S 6 5 4 3 2 1 0 W 7 6 5 4 3 2 1 0 S send by Data [7:0] S Start Condition OWI WRITE, 1 Command Byte, no Data: Device Slave Address [6:0] Data [15:8] Command Byte [7:0] S Stop Condition W Write Bit (Write = 0) 5 Device Slave Address (example: Bit 5) 2 Data Bit (example: Bit 2) master Read Operation After a data request from the master to the slave by sending an address byte including a set data direction bit, the slave answers by sending data from the interface output registers. The slave generates the data bits with a bit period equal to the last received bit (R/W bit). The master must generate a stop condition after receiving the requested data. A data request is answered by the interface module itself and consequently does not interrupt the current process of the internal microcontroller. To get certain data from the slave (e.g. EEPROM content), the appropriate command must be sent before the data request to initiate the transfer of this data into the interface output registers. This command does interrupt the current operation of the internal microcontroller and consequently also an active measurement cycle. The data in the output registers is sent continuously until a stop condition is detected, after transmitting all available data, the slave starts repeating the data. Note that during the active measurement cycle, data is continuously updated with conditioned results. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 27 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Figure 3.11 OWI Read Operation Optional OWI Read, 2 (+n) Data Bytes: S 6 5 4 3 2 1 0 R 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 S Device Slave Address [6:0] send by Data [15:8] 3rd Data Byte Data [7:0] 4th … nth Data Byte 4 data bytes are sent in a loop without resending initialization by master. Master must generate the stop condition to terminate transmission. master slave S Start Condition S Stop Condition R Write Bit (Read = 1) 5 master Device Slave Address (example: Bit 5) Data Bit (example: Bit 2) 2 OWI protocol timing and parameters are specified in Figure 3.12 and in Table 3.3. Figure 3.12 OWI Protocol Timing Start 1 0 0 1 Stop Start Write mode Read mode tOWI,STA Table 3.3 tOWI,BIT tOWI,0 tOWI,1 Symbol Min Bus free time tOWI,IDLE 25 s Hold time start condition tOWI,STA 10 s tOWI,BIT 20 Duty ratio bit “0” tOWI,0 0.125 Duty ratio bit “1” tOWI,1 1) Hold time stop condition Bit time deviation 1) tOWI,IDLE OWI Protocol Parameters Parameter Bit time tOWI,STO Typ Max Unit 8000 s 0.25 0.375 tOWI_BIT 0.625 0.75 0.875 tOWI_BIT tOWI,STO 2.0 1.0 tOWI,BIT,DEV 0.55 1.0 Conditions Between stop and start conditions Min: fOSC = 4MHz; max: fOSC = 2MHz tOWI_BIT Depends on the bit time of the last valid transmitted bit 1.5 tOWI_BIT Current bit time to previous bit time This bit time range is achievable with different frequency adjustments for minimum and maximum value. OWI communication works independently of frequency adjustment with a bit time in the range specified inTable 3.2. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 28 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 4 Interface Commands 4.1 Command Set 2 All commands are available for I C™ and OWI communication, but only in Command Mode (CM). CM is initiated by sending the command START_CM [72 D1]HEX. Every received command is answered. The answer consists of 2 bytes for the requested data or a validation code, 1-byte check sum, and 1-byte command echo. See Table 4.1 for exceptions (also refer to section 4.3). EEPROM programming must be enabled by sending the EEP_WRITE_EN command [6C F7 42]HEX. During a running measurement cycle in NOM or in CM after START_CYCx and START_ADx commands, it is mandatory to abort the measurement cycle before transmitting the next command. For safe communication, it is recommended that further communication starts with a repetition of the START_CM command. This does not apply to the read operations for getting measured values. Table 4.1 Command Set Note: See table notes at the end of the table. See Table 4.2 for a summary of responses to commands. Command (HEX) Data Command Comments Processing Time @ fOSC=3MHz 01 START_CYC_EEPOWI Start measurement cycle including initialization from EEPROM. OWI mode OWIENA is activated (refer to Table 5.5). 350µs 02 START_CYC_RAMOWI Start measurement cycle including initialization from RAM. OWI mode OWIENA is activated (refer to Table 5.5). 220µs 03 START_CYC_EEPANA Start measurement cycle including initialization from EEPROM. OWI mode OWIANA is activated (refer to Table 5.5). 350µs 04 START_CYC_RAMANA Start measurement cycle including initialization from RAM. OWI mode OWIANA is activated (refer to Table 5.5). 220µs 05 START_CYC_EEPOWIDIS Start measurement cycle including initialization from EEPROM. OWI mode OWIDIS is activated (refer to Table 5.5). 350µs 06 START_CYC_RAMOWIDIS Start measurement cycle including initialization from RAM. OWI mode OWIDIS is activated (refer to Table 5.5). 220µs 07 START_CYC_EEP Start measurement cycle including initialization from EEPROM. 350µs 08 START_CYC_RAM Start measurement cycle including initialization from RAM. 220µs READ_RAM Read data from RAM addresses 00HEX through 0EHEX. 50µs © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 29 of 50 10 to 1E Functional Description September 1, 2015 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Command (HEX) Data 30 to 43 50 Command Comments Processing Time @ fOSC=3MHz READ_EEP Read data from EEPROM addresses 00HEX through 13HEX. 50µs ADJ_OSC_ACQ Use this command with OWI communication only! Acquire frequency ratio (fOSC / fOWI) where fOSC is the frequency of internal oscillator fOWI is the OWI communication frequency Use this for adjusting the internal oscillator frequency via ADJREF:OSCADJ (see section 4.4.3). 50µs 40µs 60 2 bytes SET_DAC Set analog output AOUT to value defined by data bytes. Important note: If the data byte is outside the allowed range of 0100HEX to 14FFHEX, the IC will enter DM and output the LDR (Lower Diagnostic Range). See section 2.6. The AOUT pin goes into tri-state during processing of the command. 61 2 bytes START_AD_CNT Process <n> times A/D conversion for bridge sensor signals and for calibration temperature including autozero compensation (see section 4.4.2). data[15:0] is number <n> of measurements to process. 100µs + (4n) A/D conversion time Digital Low-Pass Filter averaging coefficient LPFAVRG from RAM is applied. Returns most recent two result values (Bridge, Calibration Temperature) while processing measurement. Last values remain if measurement is finished. See section 4.4.2 for details. 62 2 bytes START_AD_CNT_AVRG Process <n> times A/D conversion for bridge sensor signals and for calibration temperature including autozero compensation (see section 4.4.2). data[15:3] is number <n> of measurements to process. data[2:0] is digital Low-Pass Filter averaging coefficient with range [0; 7]. Note that data[2:0] changes LPFAVRG in RAM. 100µs + (4n) A/D conversion time Returns most recent two result values (Bridge, Calibration Temperature) while processing measurement. Last values remain if measurement is finished. See section 4.4.2 for details. 65 2 bytes ADJ_OSC_WRI Functional Description September 1, 2015 Write to RAM and activate Oscillator Adjust value ADJREF:OSCADJ. Returns complete new configuration word ADJREF. © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 50µs 30 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Command (HEX) Data Command Comments Processing Time @ fOSC=3MHz 6C 2 bytes EEP_WRITE_EN Enable data write to EEPROM. To be sent with data F742HEX. Other data disables EEPROM write. Returns C36CHEX if EEPROM programming is enabled. Returns CF6CHEX if EEPROM programming is disabled. 50µs 72 1 byte Start Command Mode (CM). To be sent with data D1HEX. Returns C372HEX if CM is enabled. Returns Error code if sent during Diagnostic Mode (DM). 50µs 50µs START_CM 80 to 8E 2 bytes WRITE_RAM Write data to RAM addresses 00HEX through 0EHEX. A0 to B2 2 bytes WRITE_EEP Write data to EEPROM addresses 00HEX through 12HEX. Note that there is no write access to ZMDI word at address 13HEX. Returns CF00HEX if EEPROM programming is disabled. 12.5ms C0 COPY_EEP2RAM Copy content of EEPROM address 00HEX through 0EHEX to RAM. Restores EEPROM configuration in RAM. Does not process EEPROM signature check. Returns C3C0HEX if command is processed. 130µs C3 COPY_RAM2EEP Copy content of RAM address 00HEX through 0EHEX to EEPROM. Generates EEPROM signature, writes it to address FHEX. Returns C3C3HEX if copy is successfully processed. Returns CFC3HEX if copy failed. Returns CF00HEX if EEPROM programming is disabled. 200ms C7 REFRESH_EEP Refreshes content of EEPROM addresses 00HEX through 13HEX. Detected 1-bit errors are corrected. If multi-bit error is detected, refresh is not processed. Returns C3C7HEX if refresh is successfully processed. Returns CFC7HEX if refresh failed. Returns CF00HEX if EEPROM programming is disabled. Refresh must be done by user if a wafer product (not assembled tested dice) is used. 200ms C8 GET_EEP_SIGN Calculate and return EEPROM signature. 150µs C9 GEN_EEP_SIGN Calculate and return EEPROM signature and write it to EPROM address 0FHEX. Returns CF00HEX if EEPROM programming is disabled. 12.6ms CA GET_RAM_SIGN Calculate and return RAM signature. 150µs Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 31 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Command (HEX) Command Processing Time @ fOSC=3MHz Comments CF ROM_VERSION Get Hardware and ROM revision. ZSSC3131 à 107FHEX ZSSC3135 à 1057HEX ZSSC3136 à 1007HEX ZSSC3138 à 105AHEX D0 START_AD_BR Start cyclic A/D conversion at bridge sensor channel. D1 START_AD_T Start cyclic A/D conversion at calibration temperature 1) channel. D2 START_AD_SSCP Start cyclic A/D conversion for positively biased Sensor 1) Short Check. D3 START_AD_SAC Start cyclic A/D conversion for Sensor Aging Check 1) (bridge common mode voltage measurement). D4 START_AD_BRAZ Start cyclic A/D conversion for auto-zero at bridge sensor 1) channel. D5 START_AD_TAZ Start cyclic A/D conversion for auto-zero at calibration 1) temperature channel. D6 START_AD_SSCN Start cyclic A/D conversion for negatively biased Sensor 1) Short Check. D8 START_AD_BR_AZC Start cyclic A/D conversion at bridge sensor channel 1) including auto-zero. D9 START_AD_T_AZC Start cyclic A/D conversion at calibration temperature 1) channel including auto-zero. DA START_AD_SSCP-SSCN Start cyclic A/D conversion for positively minus negatively 1) biased Sensor Short Check. DB START_AD_SAC_AZC Start cyclic A/D conversion for Sensor Aging Check (bridge common mode voltage measurement) 1) including auto-zero. 1) 4.2 Data 50µs 1) 50µs + A/D conversion time 2 All Dx commands are used for the calibration process and return raw conversion result values via I C™ and OWI. No analog output is generated. OWI communication remains enabled during the measurement cycle. Command Processing 2 All implemented commands are available for both protocols – I C™ and OWI. If Command Mode (CM) is active, a received valid command interrupts the internal microcontroller (CMC) and starts a routine processing the received command. During this processing time, the interfaces are disabled and transmitted commands are ignored. The processing time depends on the internal system clock frequency. A command always returns data (e.g., register contents, acquired measurement data) to interface output registers, which can be read by a read request. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 32 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 4.3 Digital Output Data in Command Mode 2 Digital output data in CM consists of two 16-bit words that can be read by an I C™ or OWI read request. Content of data words depends on the previously received command. Table 4.2 Digital Output Data Resulting from Processed Commands Output Data Word 1 Mode/ Commands High Byte High Byte Low Byte Requested data check sum Processed command Success code [C3 command]HEX check sum Processed command Commands with data response Commands without data response Output Data Word 2 Low Byte Reject code [CF command]HEX Unknown commands Reject code [CF 00]HEX check sum Received command Command processing error Reject code [C0 00]HEX check sum Received command 15-bit conditioned value, error status (NOM) or Error code (DM) check sum START_CYC_x [01]HEX, [02]HEX [03]HEX, [04]HEX [05]HEX, [06]HEX [07]HEX, [08]HEX 00HEX (refer to section 3.2) START_AD_CNT [61]HEX START_AD_CNT_AVRG [62]HEX Measured raw Bridge sensor value Measured raw Calibration Temperature value The check sum is calculated with following formula: check sum = FFHEX – (HighByte1st_word + LowByte1st_word)8LSB. During running measurement cycle in NOM or in CM after START_CYC_x or START_AD_x commands, an apparent check sum mismatch can occur. The digital output data, including the check sum, are updated continuously processing these commands. If an update of data is processed during readout of a 16-bit data word, the subsequent readout delivers the new but mismatched check sum. The data word belonging to that new check sum would be read if the master proceeded to read an additional data word. This might allow a check sum protection algorithm. Nevertheless, if the measurement cycle is faster than the digital readout data rate, a check sum evaluation is not applicable. Figure 4.1 Assignment of Check Sum for Continuously Updated Data Values Measurement cycle Digital data readout driven by master Functional Description September 1, 2015 Next measurement step End of a measurement causes an update of data word including CRC in the digital interface output registers ... Data Word ( i ) High Byte Low Byte CheckSumi+1 0x00 Data Word (i+1) High Byte CheckSumi+1 0x00 ... Low Byte © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 33 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 4.4 Detailed Description for Particular Commands 4.4.1 Start Command Mode with START_CM [72 D1]HEX Starting the Command Mode from Normal Operation Mode or Diagnostic Mode requires transmitting the 2 START_CM command via I C™ or OWI as shown in Figure 4.2. Figure 4.2 START_CM Command I2C WRITE, Command Byte [72D1HEX] – START_CM command: S 1 1 1 1 0 0 0 W A 0 1 1 1 0 0 1 0 A 1 1 0 1 0 0 0 1 A S Device Slave Address [78hex] S Start Condition 5 Command [72hex] Data [D1hex] Wait for Slave ACK S Stop Condition Device Slave Address (Example: Bit 5) 2 A Acknowledge (ACK) W Write Bit (Write = 0) Data Bit (Example: Bit 2) The START_CM command should also be used to stop the measurement cycle after the START_CYC_x command [0x]HEX or after START_AD commands [Dx]HEX. Recommendation: For secure operation, send the START_CM command twice and check success by reading the success code C372 HEX. Under specific ZSSC313x internal conditions, it is possible that an IC does not answer to its assigned unique slave address. In this case, use the general call address to restart communication access. 4.4.2 Acquisition of Raw Measurement Data with Commands START_AD_CNT [61]HEX and START_AD_CNT_AVRG [62]HEX The START_AD_CNT [61]HEX and START_AD_CNT_AVRG [62]HEX commands are used for synchronized raw data acquisition during the calibration process (snapshot mode). Bridge sensor signal and calibration temperature values are captured concurrently. Especially for mass calibration, it enables a raw data snapshot for all attached devices under temperature drift and pressure leakage conditions. The START_AD_CNT command [61]HEX transmits two data bytes containing the A/D conversion cycle count to be processed. The START_AD_CNT_AVRG command [62]HEX transmits two data bytes containing the following parameters: data[15:3] is the A/D conversion cycle count to be processed. data[2:0] is the digital Low-Pass Filter averaging coefficient AVRG for all measured values. Note that this overwrites the filter coefficient LPFAVRG in RAM. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 34 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Data acquisition is low-pass filtered as shown in equation (18): X OUT ,i X OUT ,i1 Xi X OUT,i1 2 AVRG i 0, AVRG 0;7 (18) The recommended value for the requested conversion cycle count is at least (2 AVRG + 8). A/D conversion is done cyclically over both input channels including auto-zero. While measuring, the most recent result values can be read out by read request. No analog output is generated. OWI communication remains enabled during the measurement cycle. When finishing the A/D conversion cycles, the read request delivers final filtered result values for the measured bridge sensor signal and calibration temperature (refer to Table 4.2). 4.4.3 Oscillator Frequency Adjustment with ADJ_OSC_ACQ [50HEX] and ADJ_OSC_WRI [65 data]HEX ADJ_OSC_x commands are used to adjust the frequency of the internal oscillator. This frequency is adjustable in the range of 2MHz to 4MHz. It has a directly proportional effect on the A/D conversion time. The internal oscillator frequency can be adjusted by ADJREF:OSCADJ. The frequency is adjusted by steps with one step equal to approximately -125kHz (frequency is decreased if ADJREF:OSCADJ is increased). The ADJ_OSC_ACQ command is sent first. This command is valid ONLY with one-wire communication (OWI). It returns a value that represents the ratio f OSC/fOWI of the internal oscillator frequency to the communication 2 frequency. This frequency ratio can be read with an I C™ or OWI Read Request. The communication frequency fOWI is known, so the current internal oscillator frequency f OSC can be calculated. Note that the resolution of the frequency measurement is better when a lower OWI communication frequency is used. The required adjustment of ADJREF:OSCADJ to reach the target frequency can be calculated from the ratio fOSC/fOWI and the adjustment increment of -125kHz/step. The ADJ_OSC_WRI command is used to write ADJREF:OSCADJ to RAM and to activate the new adjustment. The command returns the complete configuration word ADJREF (all other configuration bits retain their value). This sequence allows an easy and accurate adjustment of the internal frequency during end-of-line calibration. Table 4.3 Oscillator Frequency Adjust Sequence Command [HEX] Data [HEX] Description 72 D1 START_CM 50 - ADJ_OSC_ACQ READ - 2 bytes Steps Start Command Mode using OWI interface Acquire frequency ratio and convert to decimal Calculate the frequency: fOSC = fOWI ∗ fRATIO [MHz] and correction steps and convert to HEX: Steps = fOSC −fTARGET 125kHz 9.9 ≈ 10DEC = AHEX 3D - Read EEPROM READ - 4 bytes 65 ADJREF ADJ_OSC_WRI Functional Description September 1, 2015 Steps = fOSC -fTARGET 125kHz = 3.838MHz-2.6MHz 125kHz = Read the ADJREF register to determine the present OSCADJ settings (bits 0:4) OSCADJNEW = OSCADJ + Steps Write to RAM and activate the new ADJREF register content. © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 35 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 5 EEPROM and RAM 5.1 Programming the EEPROM Programming the EEPROM is done using an internal charge pump to generate the required programming voltage. The timing of the programming pulses is controlled internally. The programming time for a write operation is typically 12.5ms independent of the programmed clock frequency (ADJREF:OSCADJ). Waiting a minimum of 15ms per write operation before starting the next communication is recommended. To program the EEPROM, the ZSSC313x must be set to Command Mode by the command START_CM [72 D1]HEX and EEPROM programming must be enabled by the command EEP_WRITE_EN [6C F7 42]HEX. Writing data to the EEPROM is done via the serial digital interface by sending specific commands (refer to section 4.1). The WRITE_EEP command includes the address of the targeted EEPROM word and is followed by two data bytes. During EEPROM programming, the serial digital interface is disabled and no further commands can be recognized. The COPY_RAM2EEP command writes the contents of the RAM mirror area to the EEPROM. This is to simplify the calibration process when the ZSSC313x is configured iteratively. The EEPROM signature, which is not mirrored in RAM, is generated, written to EEPROM, and returned to the interface output register. This copy operation includes 16 EEPROM write operations and therefore typically requires 200ms (recommended wait time 250ms). The REFRESH_EEP command is available to refresh EEPROM content during calibration process. Particularly if unassembled tested dice (wafer product) are utilized, this refresh is mandatory to ensure proper function of EEPROM and data consistency for stored traceability data. 5.2 EEPROM and RAM Contents The configuration of the ZSSC313x is stored in 20 EEPROM 16-bit words. Calibration coefficients for conditioning the sensor signal via conditioning calculations and output limits are stored in 11 words. There are three words for setting the configuration of the ZSSC313x for the application. One register is used for storing the EEPROM signature, which is used in NOM to check the validity of the EEPROM contents after power-on. Three additional 16-bit words are available for optional user data. After every power-on, the EEPROM contents are mirrored to RAM. After this read out, the contents of the RAM mirror are checked by calculating the signature and comparing it to the one stored in EEPROM. If a signature error is detected, the ZSSC313x changes to steady Diagnostic Mode (DM). DM is indicated by setting both analog 2 outputs AOUT to the Lower Diagnostic Range (LDR). Subsequently the error code can be read out via I C™ or OWI. The configuration of the device is done from the mirrored area in RAM, so the configuration words are subsequently transferred to the internal registers. The calibration coefficients for the conditioning calculations are also read from RAM. As a result, every change to the RAM mirror area impacts the configuration and behavior of the device after the next start of the measurement cycle. After power-on, the contents of the RAM mirror area are determined by the EEPROM contents and can then be changed by specific commands writing to RAM. This new configuration can be activated by the START_CYC_RAMx commands or by the START_AD_x commands. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 36 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Table 5.1 EEPROM and RAM Content RAM/EEPRO M Address RAM/EEPROM Write Command Default Description Configuration Note: The MSB is given first if an address has more than one assignment. Conditioning Coefficients – Correction Formula Bridge Sensor Signal (section 2.3) 0 80HEX /A0HEX 1000HEX c0 – Bridge offset 1 81HEX / A1HEX 4000HEX c1 – Bridge Gain 2 82HEX / A2HEX 0000HEX c2 – Non-linearity correction 2 nd order rd 3 83HEX / A3HEX 0000HEX c3 – Non-linearity correction 3 order 4 84HEX / A4HEX 0000HEX c4 – Temperature coefficient for bridge offset 1 order 5 85HEX / A5HEX 0000HEX c5 – Temperature coefficient for bridge offset 2 st nd order st 6 86HEX / A6HEX 0000HEX c6 – Temperature coefficient gain 1 order 7 87HEX / A7HEX 0000HEX c7 – Temperature coefficient gain 2 nd order Conditioning Coefficients – Filter and Limit the Analog Output at the AOUT Pin (sections 2.5 and 2.6) 8 88HEX / A8HEX 0800HEX AOUTMIN - Lower limit for analog output at AOUT LPFAVRG – Low-Pass Filter averaging coefficient (13MSB) (3LSB) 9 89HEX / A9HEX A7F8HEX AOUTMAX - Upper limit for analog output at AOUT LPFDIFF – Low-Pass Filter differential coefficient (13MSB) (3LSB) FF00HEX ZSSC3136 only: CMVMAX – Upper limit common mode voltage (SAC) (8MSB) CMVMIN – Lower limit common mode voltage (SAC) (8LSB) Note: Set to FF00HEX for ZSSC3131, ZSSC3135, and ZSSC3138. Sensor Aging Check (SAC) Limits AHEX (10) 8AHEX / AAHEX Configuration Words (section 5.3) BHEX (11) 8BHEX / ABHEX 01D2HEX CFGAFE - Configuration of analog front-end CHEX (12) 8CHEX / ACHEX 0458HEX CFGAPP - Configuration of target application DHEX (13) 8DHEX / ADHEX 2112HEX ADJREF - Adjustment of system, communication settings etc. EHEX (14) 8EHEX / AEHEX 0000HEX CFGSF - Configuration of safety functions - / AFHEX 7391HEX Signature Signature FHEX (15) Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 37 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family RAM/EEPRO M Address RAM/EEPROM Write Command Default Description Configuration Note: The MSB is given first if an address has more than one assignment. Free Memory Available for Optional Use by User Applications (not included in signature) 10HEX (16) - / B0HEX 0000HEX Free user memory, not included in signature 11HEX (17) - / B1HEX 0000HEX Free user memory, not included in signature 12HEX (18) - / B2HEX 0000HEX Free user memory, not included in signature 13HEX (19) -/- No customer access - ZMDI restricted use Note: The contents of the EEPROM registers at delivery are not specified and can be subject to changes. Particularly with regard to traceability, the contents can be unique per die. Note that contents at delivery might not have a valid signature. Consequently the ZSSC313x would start in the Diagnostic Mode. Note: All registers must be rewritten during the calibration procedure. 5.2.1 Traceabilty ZMDI can guarantee the EEPROM contents for packaged parts only. On delivery of bare dice, the EEPROM content might be changed by flipped bits due to electrostatic effects, which could occur during the wafer sawing. The ZSSC313X features three 16-bit registers reserved for user data: 10HEX, 11HEX, and 12HEX. For example, these can be used for an ID number. There are no restrictions for the content of these registers; they can be read 2 via I C™ at any time. When using ZACwire TM communication (OWI), READ is possible if ZACwire™ communication is enabled. WRITE is possible if the EEPROM lock is disabled. WRITE is possible if an EEPROM error (wrong signature or multi-bit error) is detected. During final test, ZMDI writes the following manufacturing data to these registers: Register 10HEX: bits 15:0 = lot number part 1 (MSB section) Register 11HEX: bits 15:5 = lot number part 2 (LSB section) / bits 4:0 = wafer number Register 12HEX bits 15:8 = wafer x-position / bits 7:0 = wafer y-position Table 5.2 temp lotNbr waferNbr xpos ypos Lot, Wafer, x-Position, and y-Position Number Calculation Procedure = = = = = reg0x10 * 2048 + (reg0x11&0xFFE0)/32; NumberConvert(temp, BASE); // BASE = 36 reg0x11&0x1F; reg0x12&0xFF00)/256; reg0x12&0x00FF; ZMDI recommends saving these data in the calibration log to identify the device in the event that RMA processing is needed. Register 13HEX is used by ZMDI to store logistic data and internal information. It can be written by ZMDI via test equipment only; the user cannot write data to this register. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 38 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 5.2.2 EEPROM Error Correction The EEPROM data are stored with HAMMING DISTANCE = 3, which means 100% detection and correction of 1-bit errors 100% detection of 2-bit errors The detection of multi-bit errors (>2 bit) is processed at a lower detection rate. 5.3 Configuration Words The data stored in EEPROM at addresses BHEX to EHEX determine the configuration of the ZSSC313x, as explained in the following tables. Table 5.3 Configuration Word CFGAFE Bit CFGAFE - Configuration of Analog Front-End EEPROM/RAM Address BHEX (11) 15 ZSSC3138 BRidge sensor channel eXtended Zero Compensation POLarity (offset compensation by analog front-end—refer to section 2.1) 0: negative – compensates positive offsets 1: positive – compensates negative offsets BRXZCPOL (Set 0 for ZSSC3131, 3135 and 3136.) 14:10 ZSSC3138 BRidge sensor channel eXtended Zero Compensation value (offset compensation by analog front-end—refer to section 2.1) BRXZC Offset compensation is only active, if BRXZC 0 The offset compensation step depends on the selected input span. (Set to 0 for ZSSC3131, ZSSC3135, and ZSSC3136.) 9:6 BRridge sensor channel GAIN (aIN - refer to section 2.1) 0100BIN: 105 0101BIN: 70 0110BIN: 52.5 0111BIN: 35 1000BIN: 26.25 1001BIN: 14 ZSSC3138 High Gain Mode: 0000BIN: 420 0001BIN: 280 5 BRGAIN 1010BIN: 9.3 1011BIN: 7 11ddBIN: 2.8 0010BIN: 210 0011BIN: 140 A/D Conversion SLOW mode ADCSLOW Doubles A/D conversion time to improve conversion result quality (less noise, better linearity). Valid for all measurements. 0: disabled 1: enabled 4:3 A/D Conversion input Range Shift (rsADC – refer to section 2.1) 00BIN: 01BIN: 10BIN: 11BIN: Functional Description September 1, 2015 1 /16 à ADC range 1 /8 à ADC range ¼ à ADC range ½ à ADC range = [ (–1/16 VADC_REF ) = [ (–1/8 VADC_REF ) = [ (–1/4 VADC_REF ) = [ (–1/2 VADC_REF ) ADCRS to (+15/16 VADC_REF)] to (+7/8 VADC_REF)] to (+3/4 VADC_REF)] to (+1/2 VADC_REF)] © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 39 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Bit CFGAFE - Configuration of Analog Front-End EEPROM/RAM Address BHEX (11) 2:1 A/D Conversion RESolution (rADC - refer to section 2.1) ADCRES Valid for bridge signal as well as for temperature measurement. 00BIN: 13bit 01BIN: 14bit ZSSC3138 Digital Value Range Zooming (refer to section 2.2): 10BIN: 15bit 11BIN: 16bit If 15bit or 16bit are activated use CFGAPP:BROFFS to select segment to be used for bridge sensor signal. Conditioning calculation is done with zoomed 13bit or 14bit value, respectively (refer to section 2.2). 0 ZSSC3138 High Sample Rate Mode (AD Conversion ORDer) 0: disabled (1-step conversion) 1: ADCORD enabled (2-step conversion) Note: Set to 0 for ZSSC3131, ZSSC3135, and ZSSC3136. Table 5.4 Bit 15:13 Configuration Word CFGAPP CFGAPP - Configuration of Target Application EEPROM/RAM Address CHEX (12) ZSSC3138 Digital Value Range Zooming Offset (refer to section 2.2): Digital offset to raw bridge sensor value. BROFFS Note: Set to 000BIN for ZSSC3131, ZSSC3135, and ZSSC3136. 12 Count of Bridge Sensor measurements per special measurement in measurement cycle loop 0: 1 Bridge Sensor signal and 1 special measurement 1: 30 Bridge Sensor signal and 1 special measurement BRCNT 11 ZSSC3136 ROM check at power-on Start-up is increased approx. 10ms. 0: disabled CHKROM 10 1: enabled ZSSC3135, ZSSC3136, ZSSC3138 Sensor Short Check Increased Limit 0: limit = 1750 counts 1: limit = 2280 counts CHKSSCL Note: Set to 0 for ZSSC3131. 9 ZSSC3135, ZSSC3136, ZSSC3138 Sensor Connection and Short Check 0: disabled 1: enabled CHKSENS Note: Set to 0 for ZSSC3131. 8 ZSSC3135, ZSSC3136, ZSSC3138 Temperature Sensor Check 0: disabled 1: enabled CHKTS Note: Set to 0 for ZSSC3131. 7:6 Temperature measurement GAIN (refer to section 6): 00BIN: Functional Description September 1, 2015 2.66 01BIN: 4.0 10BIN: TGAIN 6.6 11BIN: 7.33 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 40 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Bit CFGAPP - Configuration of Target Application 5:4 Temperature Measurement Mode 01BIN: 11BIN: EEPROM/RAM Address CHEX (12) TMM internal on-chip diode – correlated with zero point at ADJREF:TOFFS = 0 internal on-chip diode – correlated with zero point at ADJREF:TOFFS = 2 ZSSC3135 and ZSSC3136 External Temperature Sensor 00BIN: external diode at pin IRTEMP 10BIN: external voltage at pin IRTEMP 3 CoNneCT SENSor internally to supply voltage CNCTSENS VBR_T is connected to VDDA and VBR_B is connected to VSSA 0: disconnected 1: connected 2 Reserved. Set to 0. 1 A/D conversion REFerence voltage for Bridge Sensor signal (VADC_REF - refer to section 2.1) 0: 0 Bit 15:14 VADC_REF = VVBR_T – VVBR_B positive (VIN_DIFF = VVBP – VVBN) BRREF VADC_REF = VVDDA – VVSSA 1: BRidge Sensor POLarity ( VIN_DIFF - refer to section 2.1) 0: Table 5.5 - BRPOL negative (VIN_DIFF = VVBN – VVBP) 1: Configuration Word ADJREF ADJREF – Adjustment of Internal References EEPROM/RAM Address DHEX (13) One-Wire Interface Mode (refer to section 3.4 for details) IFOWIM Pin AOUT IFOWIM 13:10 9 8:6 5 4:0 OWI Mode OWI Analog Output 00 OWIWIN Start-up window After start-up window 01 OWIANA Start-up window Enabled 10 OWIENA Enabled Disabled 11 OWIDIS Disabled Enabled 2 Unique slave address for I C™ and OWI. address = 70HEX + IFADDR Resulting address range is 70HEX to 7FHEX. General address 78HEX is always valid. IFADDR Enables triggering a reset if the Diagnostic Mode (DM) occurs 0: stop and DM 1: reset and startup Reset is executed after time-out of watchdog. DMRES Adjust zero point of temperature measurement TOFFS Enables bias current boost for analog front-end 0: disabled 1: enabled Activation is recommended for oscillator frequency > 3MHz. BBOOST Adjustment of internal oscillator frequency fOSC’ in the range of 2 to 4MHz OSCADJ Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 41 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Table 5.6 Bit Configuration Word CFGSF CFGSF – Configuration of Safety Functions EEPROM/RAM Address EHEX (14) Reserved. Set to 000HEX. - 5 ZSSC3136 Main Channel A/D Conversion Result Check High Limit 0: disabled 1: enabled Note: Set to 0 for ZSSC3131, ZSSC3135, and ZSSC3138. CHKMCCH 4 ZSSC3136 Main Channel A/D Conversion Result Check Low Limit 0: disabled 1: enabled Note: Set to 0 for ZSSC3131, ZSSC3135, and ZSSC3138. CHKMCCL 3 ZSSC3135, ZSSC3136, ZSSC3138 Sensor Short Check Disable 0: enabled 1: disabled Note that CFGAPP:CHKSENS enables both the Sensor Short Check and the Sensor Connection Check. SSCDIS disables the Sensor Short Check and allows enabling of the Sensor Connection Check only. Note: Set to 0 for ZSSC3131. SSCDIS 2 Reserved. Set to 0. - 1 Enables enhanced Bridge Settling Mode 0: disabled 1: 15:6 0 BSETTL enabled Enables the EEPROM lock for OWI communication 0: disabled 1: enabled Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. EEPLOCK 42 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 5.4 EEPROM Signature The EEPROM signature (address FHEX) is used to check the validity of the EEPROM contents. The signature is built using a polynomial arithmetic modulo 2. The following source code generates the signature if the field eepcont[ ] is allocated by the EEPROM content (addresses 00HEX to EHEX). The parameter N is the count of applicable addresses and must be set as N=15. Figure 5.1 Source-Code Signature Generation #define POLYNOM A005HEX unsigned short signature(eepcont, N) unsigned short eepcont[], N; { unsigned short sign, poly, p, x, i, j; sign = 0; poly = POLYNOM; for (i=0; i<N; i++) { sign^=eepcont[i]; p=0; x=sign&poly; for (j=0; j<16; j++, p^=x, x>>=1); sign<<=1; sign+=(p&1); } return(~sign); } 5.5 EEPROM Write Locking The ZSSC313x supports EEPROM write locking (EEPLOCK). If the EEPROM lock is active (CFGSF:EEPLOCK=1), it is not possible to enable EEPROM programming with the command EEP_WRITE_EN using one-wire communication (OWI); the ZSSC313x answers the command EEP_WRITE_EN with reject code CF6CHEX, and a subsequent EEPROM write access is blocked. 2 2 An activated EEPLOCK does not block writing to the EEPROM using I C™ and can always be reset using I C™. EEPLOCK is active only if programmed into EEPROM and activated due to - New power-on or - Receiving the EEP_WRITE_EN command or - Starting the measurement cycle by receiving the START_CYC_x command The following write sequence is possible: - Write calibration data including EEPLOCK to RAM mirror - Enable EEPROM writing by sending the command EEP_WRITE_EN - Copy the RAM mirror to EEPROM - Write the EEPROM signature directly to EEPROM If an invalid EEPROM signature is detected, the EEPROM lock is always deactivated. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 43 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 6 Application Recommendations: Temperature Sensor Adaption 6.1 Temperature Measurement The Calibration Temperature sensor is selected by the CFGAPP:TMM configuration bits. Adjustment of gain (CFGAPP:TGAIN) and offset (ADJREF:TOFFS) fits the temperature signal to the analog front-end input range. Table 6.1 shows available configurations for different types of temperature sensors. Table 6.1 Configuration Temperature Measurement Gain TGAIN Offset Adjust TOFFS Internal Diode GT1 – GT4 0 or 2 (depends on TMM) External Diode GT1 – GT4 0 to 7 VBR_T, IRTEMP External Resistor GT1 – GT4 0 to 7 IRTEMP ZSSC3135 ZSSC3136 Temperature Sensor Sensor Connected to/between Pin(s) Notes Recommended: TMM = 01BIN, TGAIN = GT2 Use a diode in forward direction Use a half-bridge between VDDA to VSSA Recommendation: Fit the temperature signal including tolerances to a range of 10% to 90% of the ADC range. Use the START_AD_T command for recording the relevant raw data values. 6.2 On-Chip PN-Junction Temperature Sensor The sensitivity of the temperature measurement using the on-chip sensor depends on the selected temperature gain CFGAPP:TGAIN. Table 6.2 Sensitivity of On-Chip Temperature Sensor Sensitivity s [ppm FS / K] Gain TGAIN Minimum Typical Maximum GT1 (00BIN) 1350 1450 1600 GT2 (01BIN) 3350 3650 4050 GT3 (10BIN) 3700 4050 4450 GT4 (11BIN) 4000 4400 4850 Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 44 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 6.3 External pn-Junction Temperature Sensor (ZSSC3135 and ZSSC3136 only) The ZSSC3135 and ZSSC3136 support the application of an external diode connected to the IRTEMP pin as the temperature sensor. Typical diodes deliver a nominal voltage of 650mV at room temperature and with a temperature coefficient of -2mV/K. VT 12 VBR_T IRTEMP ZSSC313x Figure 6.1 External pn-Junction Temperature Sensor (ZSSC3135 and ZSSC3136 only) Temperature Sensor The sensitivity of temperature measurement using the external sensor depends on selected temperature gain CFGAPP:TGAIN. Offset compensation must be adjusted with ADJREF:TOFFS. Table 6.3 and Table 6.4 show an estimation for temperature signal range and sensitivity. Adjust the temperature measurement by checking the raw temperature values recorded with the START_AD_T command. Table 6.3 Sensitivity and Signal Range of the External pn-Junction Temperature Sensor Maximum Signal Range VT,RANGE [mV] For Temperature Sensor over Operating Temperature Range Sensitivity s [ppm FS / mV] Gain TGAIN Min Typical Max GT1 (00BIN) 610 670 740 970 GT2 (01BIN) 1520 1670 1850 380 GT3 (10BIN) 1670 1830 2030 350 GT4 (11BIN) 1820 2000 2220 320 Table 6.4 Signal Range Center Voltage of External pn-Junction Temperature Sensor Temperature Signal Range Center Voltage VT,CENTER [mV] Offset Adjust TOFFS 0 1 2 3 4 5 6 7 Typical +/-20% 667 625 583 542 500 458 417 375 Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 45 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family The following example demonstrates the method for determining TGAIN and TOFFS for a specific pn-junction temperature sensor. Example: Temperature sensor: 6.4 Sensitivity sTS = -2.1mV/K Signal voltage at 25°C VTS(T = 25°C) = 660mV Operating temperature T = -40°C to 125°C Operating temperature range dT = 165grd Signal range of temperature sensor VTS,RANGE = sTS • dT = 346.5mV Select TGAIN = 10BIN (GT3) VTS,RANGE = 346.5mV ≤ 350mV = VT,RANGE_GT3 Signal voltage at center operation temperature VTS,CENTER(T = 42.5°C) = 623mV Select TOFFS = 1 (VT,CENTER_3) VTS,CENTER = 623mV ≈ 625mV = VT,CENTER_1 External Resistive Temperature Sensor (ZSSC3135 and ZSSC3136 only) Figure 6.2 External Resistive Temperature Sensor (ZSSC3135 and ZSSC3136 only) Half-Bridge IRTEMP ZSSC313x R(T) VDDA VT VDDA VSSA Temperature Sensor The ZSSC3135 and ZSSC3136 support the application of an external resistive half-bridge between the pins VDDA and VSSA connected to the IRTEMP pin as the temperature sensor. An asymmetric resistor ratio is used to generate an input voltage in the range of (VDDA - 1V) to (VDDA – 0.2V). The temperature signal voltage VT is ratiometric to the supply voltage VDDA. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 46 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family Table 6.5 shows an estimation for the temperature signal range and sensitivity. Adjust the temperature measurement by checking the raw temperature values recorded with the START_AD_T command Table 6.5 Sensitivity and Signal Range of the External Resistive Temperature Sensor Temperature Signal Range VT / VDDA [mV/V] Gain TGAIN Sensitivity [ppm FS / mV/V] GT1 (00BIN) 2666 GT2 (01BIN) GT3 (10BIN) GT4 (11BIN) Functional Description September 1, 2015 Offset Adjust TOFFS 0 1 2 3 4 5 6 7 min 20 20 20 20 20 20 20 20 max 350 340 330 320 310 300 290 280 min 95 85 70 60 50 40 30 20 max 240 230 220 210 200 190 180 166 min 100 90 80 70 60 50 40 30 max 230 220 210 200 190 180 170 160 min 105 95 85 75 65 55 45 35 max 225 215 205 195 185 175 165 155 6666 7333 8000 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 47 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 7 Related Documents Note: X_xy refers to the current revision of the document. Documents marked with an asterisk (*) are available on request (see page Error! Bookmark not defined.). Document File Name ZSSC313x Data Sheet (See individual product data sheets) ZSSC313x_Data_Sheet_Rev_X_xy.pdf ZSSC313x Evaluation Kit Description ZSSC313x_Evaluation_Kit_Description_Rev_X_xy.pdf ZSSC3131/ZSSC3136 Application Notes— Automotive Sensor Switch ZSSC3131_ZSSC3136_AN_Automotive_Sensor_Switch_Rev_X_xy.pdf ZSSC313x Tech Note—High Voltage Protection* ZSSC313x_Tech_Note_HighVoltageProt_Rev_X_xy.pdf SSC Temperature Profile Calculation Spread Sheet SSC_Temperature_Profile_Calculation_Rev_X_xy.xls ZSSC313x Tech Note—EMC Design Guidelines* ZSSC313x_TN_EMC_Design_Guidelines_Rev_X_xy.pdf ZSSC313x Technical Note – Calibration DLL Description ZSSC313x_TN_Cal_DLL_Description_Rev_X_xy.txt SSC Communication Board Command Syntax ** SSC_CommunicationBoard_CommandSyntax_rev_X_xy.xls Visit the product page for the ZSSC3131/ ZSSC3135/ ZSSC3136/ ZSSC3138 on ZMDI’s website www.zmdi.com or contact your nearest sales office for the latest version of these documents. * Note: Documents marked with an asterisk (*) require a free customer login account. To set up an account, click on Login in the upper right corner of the website at www.zmdi.com and follow the instructions. ** Note: Documents marked with a double asterisk (**) are available on the Evaluation Tools web page at http://www.zmdi.com/ssc-tools. Functional Description September 1, 2015 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 48 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 8 Glossary Term Description ADC Analog-to-Digital Converter AOUT Analog Output BR Bridge Sensor Signal CM Command Mode CMC Calibration Microcontroller CMV Common Mode Voltage DAC Digital-to-Analog Converter DM Diagnostic Mode EEPROM Electrically Erasable Programmable Read Only Memory LDR Lower Diagnostic Range MSB Most Significant Bit NOM Normal Operation Mode OWI One-Wire Interface RAM Random-Access Memory ROM Read-Only Memory S Sensor Signal SAC Sensor Aging Check SCC Sensor Connection Check SSC Sensor Signal Conditioner or Sensor Short Check depending on context SSCP Positive-biased Sensor Short Check SSCN Negative-biased Sensor Short Check T Temperature Sensor Signal TS Temperature Sensor TSC Temperature Sensor Check UDR Upper Diagnostic Range XZC eXtended Zero Compensation Functional Description © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. September 1, 2015 49 of 50 ZSSC313x Automotive Resistive Sensor Signal Conditioner Family 9 Document Revision History Revision Date Description 1.00 October 28, 2011 First release of document. 1.01 December 07, 2011 ZSSC3135 support external temperature sensor (sections 6.3 and 6.4) 1.02 January 18, 2012 Correct filter function for raw measurement data acquisition (section 4.4.2) 1.03 November 12, 2013 Update for contact information and imagery for cover and headers. SET_DAC command behavior specified in section 2.6 on analog output signal range and limitation. Edits to oscillator adjustment sequence in Table 4.3. Updates to related documents section. 1.04 September 1, 2015 Correction in section 2.5 for “Digital Filter Function” readout values via I C™ and OWI. CRC changed to check sum. Section 2.1 on A/D conversion updated. Section 2.2 on digital zooming updated (applies to ZSSC3138 only). Update for Table 5.1 including addition of default values. Traceability information added (section 5.2.1). EEPROM error correction description added (section 5.2.2). Contact information and cover imagery updated. Related documents updated. Sales and Further Information 2 www.zmdi.com [email protected] Zentrum Mikroelektronik Dresden AG Global Headquarters Grenzstrasse 28 01109 Dresden, Germany ZMD America, Inc. 1525 McCarthy Blvd., #212 Milpitas, CA 95035-7453 USA Central Office: Phone +49.351.8822.306 Fax +49.351.8822.337 USA Phone 1.855.275.9634 Phone +1.408.883.6310 Fax +1.408.883.6358 European Technical Support Phone +49.351.8822.7.772 Fax +49.351.8822.87.772 DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are subject to change without notice. Zentrum Mikroelektronik Dresden AG (ZMD AG) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. The information furnished hereby is believed to be true and accurate. However, under no circumstances shall ZMD AG be liable to any customer, licensee, or any other third party for any special, indirect, incidental, or consequential damages of any kind or nature whatsoever arising out of or in any way related to the furnishing, performance, or use of this technical data. ZMD AG hereby expressly disclaims any liability of ZMD AG to any customer, licensee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of ZMD AG for any damages in connection with or arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability, or otherwise. European Sales (Stuttgart) Phone +49.711.674517.55 Fax +49.711.674517.87955 Functional Description September 1, 2015 Zentrum Mikroelektronik Dresden AG, Japan Office 2nd Floor, Shinbashi Tokyu Bldg. 4-21-3, Shinbashi, Minato-ku Tokyo, 105-0004 Japan ZMD FAR EAST, Ltd. 3F, No. 51, Sec. 2, Keelung Road 11052 Taipei Taiwan Phone +81.3.6895.7410 Fax +81.3.6895.7301 Phone +886.2.2377.8189 Fax +886.2.2377.8199 Zentrum Mikroelektronik Dresden AG, Korea Office U-space 1 Building Unit B, 906-1 660, Daewangpangyo-ro Bundang-gu, Seongnam-si Gyeonggi-do, 463-400 Korea Phone +82.31.950.7679 Fax +82.504.841.3026 © 2015 Zentrum Mikroelektronik Dresden AG — Rev.1.04 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 50 of 50