Application Note Rev. 1.00 / August 2013 ZSSC3154 Oscillator Frequency Adjustment Automotive ICs Adaptable and Rugged ZSSC3154 Oscillator Frequency Adjustment Contents 1 2 3 Introduction ....................................................................................................................................................... 3 Oscillator Frequency Requirements and Recommendations ........................................................................... 3 Oscillator Adjustment........................................................................................................................................ 4 3.1. Oscillator Adjustment using the ZSSC3154 Evaluation Kit ....................................................................... 4 3.2. Oscillator Adjustment using the SSC Terminal Program........................................................................... 5 4 Related Documents .......................................................................................................................................... 7 5 Glossary ........................................................................................................................................................... 7 6 Document Revision History .............................................................................................................................. 7 List of Tables Table 3.1 Table 3.2 Steps for Adjusting the Internal Oscillator Frequency f OSC with the Evaluation Kit ............................. 4 Steps for Adjusting the Internal Oscillator Frequency fOSC with the SSC Terminal Program ............. 6 Application Note August 28, 2013 © 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00 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 7 ZSSC3154 Oscillator Frequency Adjustment 1 Introduction This application note explains the procedure for the oscillator frequency adjustment and additional considerations regarding the effects of the adjustment. The ZSSC3154 Sensor Signal Conditioner IC has a feature for internal oscillator frequency (fOSC) adjustment via EEPROM configuration settings. The recommended frequency range is from 2.6MHz to 3.2MHz range which enables and provides full performance of the ZSSC3154. 2 Oscillator Frequency Requirements and Recommendations Minimum recommended oscillator frequency of 2.6MHz guarantees the 1ms response time and 1kHz bandwidth as specified for the ZSSC3154 sensor signal conditioner for both simple and complex measurements, including advanced diagnostics. To achieve low noise ADC conversion, the maximum oscillator frequency of 3.2MHz should not be exceeded. Above this frequency the analog output signal may deteriorate as well. The maximum adjustment step is guaranteed according to the test limit of 200kHz. The target frequency can be adjusted with an accuracy of 125 kHz, over the operational temperature range. Within the operational voltage range, it can deviate by an additional 35 kHz. Therefore, the adjustment accuracy is better than 6% for oscillator frequencies greater than 2.6MHz. Overall the target frequency can be expected to have accuracy of 10%. The oscillator frequency affects the ZSSC3154 calibration microcontroller (CMC) performance and therefore the following system parameters: Startup time duration, response time, sample rate, supply current, A/D conversion 1 time, start-up time, Power-on diagnostic output duration τPDO (see the ZSSC3154 Functional Description for 2 2, 3 details), I C™ interfaces (interface timing specification conditions are fOSC 2MHz), OWI interface 3 and start condition (interface timing specification conditions are fOSC 2MHz), sequential Analog Output Mode duration 1 τSEQ for a given phase of the sequential output and command processing time EEPROM programming duration is typically 12.5ms and is independent of the programmed clock frequency. The oscillator frequency can be finely adjusted in the recommended range of 2.6MHz (minimum) with a maximum of 3.2MHz. The configuration word CFGAPP2 (EEPROM/RAM address 16HEX is used to adjust fOSC: Bits 0:3 (OSCADJ: adjust frequency fOSC of internal oscillator) Bit 4 (OSCSS: enable Oscillator Spread Spectrum Mode) Using the Oscillator Spread Spectrum Mode reduces electromagnetic emission (EME). 1 2 3 Timing can be shortened by adjusting the divider CFGAPP:TIMEDIV (configuration word at EEPROM/RAM address 15HEX). I2C™ is a trademark of NXP. Internal clock frequency fOSC must be at least 5 times higher than the communication clock frequency. Application Note August 28, 2013 © 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00 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 7 ZSSC3154 Oscillator Frequency Adjustment 3 Oscillator Adjustment The steps below describe the sequence for f OSC adjustment. The objective is to determine the actual oscillator frequency and to adjust it as needed to meet design specifications. As an example, the target frequency is f OSC = 2.6MHz for the steps below. Preliminary settings: Slave address is 28HEX. OWI bit time is 1ms (fOWI = 1kHz). Oscillator adjustment bits [0:3] in CFGAPP2:OSCADJ are 0000BIN for maximum frequency and 1111BIN for minimum frequency. Target for the frequency adjustment for this example is 2.6MHz. 3.1. Oscillator Adjustment using the ZSSC3154 Evaluation Kit The ZSSC3154 Evaluation Kit can be used to provide hardware and a graphical user interface (GUI) to communicate with the ZSSC3154 to adjust f OSC. Before attempting the oscillator adjustment procedures in Table 3.1, refer to the ZSSC3154 Evaluation Kit Description for full instructions for using the kit. Table 3.1 Steps for Adjusting the Internal Oscillator Frequency fOSC with the Evaluation Kit Step #1 #2 #3 Procedure Evaluation Kit GUI Display Establish OWI communication from the main window. Command Mode is activated automatically. Read and set the IC RAM configuration in to the GUI software. In the top menu, click the icon or select “Calibration” and then “Send Command” to access the “Send Command” window. Acquire the frequency ratio (fRATIO = fOSC / fOWI) by sending the command 50HEX (ADJ_OSC_ACQ). The software automatically reads four bytes for which the first two bytes are the ratio result (0EFEHEX in adjacent example). Read the CFGAPP2 register via the RAM-EEPROM dialog or by sending the command 46HEX (READ_EEP for address16HEX). Bits [0:3] contain the present oscillator adjustment setting: 0000BIN, which corresponds to the maximum fOSC setting 3.838MHz. Application Note August 28, 2013 © 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00 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 7 ZSSC3154 Oscillator Frequency Adjustment Step Procedure #4 Convert the fRATIO readout (OEFEHEX for this example) to decimal (3838DEC) and calculate the oscillator frequency with fOWI = 1kHz. #5 Calculate the steps count for frequency adjustment to target frequency of 2.6MHz for this example. Average step size is approximately 125kHz. #6 Add the result to the existing oscillator adjustment settings and generate the new CFGAPP2 register content. #7 3.2. Evaluation Kit GUI Display CFGAPP2NEW Write the new CFGAPP2 register content to the EEPROM using the RAM-Register dialog or click the WriteRAM and RAM->EEP buttons on the main screen. The enable for EEPROM writing and signature generation are done automatically by the GUI software. Oscillator Adjustment using the SSC Terminal Program An alternate method of adjusting fOSC is to use the SSC Terminal Program, which is available for download from the ZMDI website’s “Sensor Signal Conditioner Evaluation Tools” page at http://www.zmdi.com/ssc-tools. This requires a customer login account. To obtain an account, click the Login button in the upper corner of the ZMDI website and follow the instructions to set up an account. After login, the link for downloading the current version of the SSC Terminal Program can be accessed under the “SOFTWARE” heading. The SSC Terminal Program enables sending commands to the ZSSC3154 using the OWI interface. Table 3.2 1 gives the steps for adjusting fOSC using the commands in the adjacent columns. Refer to SSC Command Syntax for more information about interface commands. This spreadsheet is included with the SSC Terminal Program download. 1 Commands can also be sent using the ZSSC3154 Evaluation Kit. Application Note August 28, 2013 © 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00 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 7 ZSSC3154 Oscillator Frequency Adjustment Table 3.2 Steps for Adjusting the Internal Oscillator Frequency fOSC with the SSC Terminal Program Command (HEX) Data (HEX) Terminal Program syntax1 Result (HEX) Step Procedure #1 Reset the CB and trigger the power supply at next command. #2 Establish OWI communication and enter the Command Mode by sending the START_CM command. 72 74 #3 Acquire frequency ratio fRATIO (the longer the OWI bit time is, the more accurate the result will be). Convert the fRATIO readout (OEFEHEX for this example) to decimal (3838DEC) and calculate the fOSC oscillator frequency with fOWI = 1kHz. 50 - OW_2800150 OR_28002 #4 Read the CFGAPP2 register to determine the present setting for OSCADJ by sending the command 46HEX (READ_EEP for address16HEX). 46 - OW_2800146 OR_28002 Result: 4810HEX OSCADJ = 0000BIN (presently set for maximum frequency, which is 3.838MHz) OSCSS = 1 BIN (Spread Spectrum Mode Enabled) #5 Adjust to the target frequency of 2.6MHz from 3.838MHz by setting OSCADJ to 10 steps (AHEX) as calculated in Table 3.1. 65 481A OW_2800365481A OSCADJ =0HEX + A HEX CFGAPP2 = 481A HEX #6 Enable data write to EEPROM 6C F742 OW_280036CF742 C36CHEX upon success #7 Write CFGAPP2new to EEPROM at address 16HEX. B6 481A OW_28003B6481A #8 Generate and write EEPROM signature by sending the GEN_EEP_SIGN command. C9 - Application Note August 28, 2013 r tso31150 os_14 t11030 OWT280027274 C372HEX upon success OW_28001C9 © 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00 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 7 ZSSC3154 Oscillator Frequency Adjustment 4 Related Documents Note: rev_X_xy refers to the current version of the document. Document File Name (where x_yy refers to the current firmware version) ZSSC3154 Data Sheet ZSSC3154_Data_Sheet_rev_X_xy.pdf ZSSC3154 Functional Description ZSSC3154_Functional_Description_rev_X_xy.pdf SSC Command Syntax SSC_CommandSyntax_Rev_x_yy.xls ZSSC3154 Evaluation Kit Description ZSSC3154_Evaluation_Kit_Description_Rev_X_xy.pdf Visit ZMDI’s website www.zmdi.com or contact your nearest sales office for the latest version of these documents. 5 Glossary Term Description CMC Calibration Microcontroller EME Electromagnetic Emission OWI One-Wire Interface 6 Document Revision History Revision 1.00 Date August 28, 2013 Description First release Sales and Further Information 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 +49.351.8822.0 Fax +49.351.8822.600 USA Phone +855.275.9634 Phone +408.883.6310 Fax +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. 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European Sales (Stuttgart) Phone +49.711.674517.55 Fax +49.711.674517.87955 Application Note August 28, 2013 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 11th Floor, Unit JA-1102 670 Sampyeong-dong Bundang-gu, Seongnam-si Gyeonggi-do, 463-400 Korea Phone +82.31.950.7679 Fax +82.504.841.3026 © 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00 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 7