SLAA322D August   2006  – July 2017 MSP430BT5190 , MSP430F1101 , MSP430F1101A , MSP430F1111A , MSP430F112 , MSP430F1121 , MSP430F1121A , MSP430F1122 , MSP430F1132 , MSP430F122 , MSP430F1222 , MSP430F123 , MSP430F1232 , MSP430F133 , MSP430F135 , MSP430F147 , MSP430F1471 , MSP430F148 , MSP430F1481 , MSP430F149 , MSP430F1491 , MSP430F155 , MSP430F156 , MSP430F157 , MSP430F1610 , MSP430F1611 , MSP430F1612 , MSP430F167 , MSP430F168 , MSP430F169 , MSP430F2001 , MSP430F2002 , MSP430F2003 , MSP430F2011 , MSP430F2012 , MSP430F2013 , MSP430F2013-EP , MSP430F2101 , MSP430F2111 , MSP430F2112 , MSP430F2121 , MSP430F2122 , MSP430F2131 , MSP430F2132 , MSP430F2232 , MSP430F2234 , MSP430F2252 , MSP430F2252-Q1 , MSP430F2254 , MSP430F2272 , MSP430F2272-Q1 , MSP430F2274 , MSP430F233 , MSP430F2330 , MSP430F235 , MSP430F2350 , MSP430F2370 , MSP430F2410 , MSP430F2416 , MSP430F2417 , MSP430F2418 , MSP430F2419 , MSP430F247 , MSP430F2471 , MSP430F248 , MSP430F2481 , MSP430F249 , MSP430F2491 , MSP430F2616 , MSP430F2617 , MSP430F2618 , MSP430F2619 , MSP430F412 , MSP430F413 , MSP430F4132 , MSP430F415 , MSP430F4152 , MSP430F417 , MSP430F423 , MSP430F423A , MSP430F425 , MSP430F4250 , MSP430F425A , MSP430F4260 , MSP430F427 , MSP430F4270 , MSP430F427A , MSP430F435 , MSP430F4351 , MSP430F436 , MSP430F4361 , MSP430F437 , MSP430F4371 , MSP430F438 , MSP430F439 , MSP430F447 , MSP430F448 , MSP430F4481 , MSP430F449 , MSP430F4491 , MSP430F4616 , MSP430F46161 , MSP430F4617 , MSP430F46171 , MSP430F4618 , MSP430F46181 , MSP430F4619 , MSP430F46191 , MSP430F47126 , MSP430F47127 , MSP430F47163 , MSP430F47166 , MSP430F47167 , MSP430F47173 , MSP430F47176 , MSP430F47177 , MSP430F47183 , MSP430F47186 , MSP430F47187 , MSP430F47193 , MSP430F47196 , MSP430F47197 , MSP430F477 , MSP430F478 , MSP430F4783 , MSP430F4784 , MSP430F479 , MSP430F4793 , MSP430F4794 , MSP430F5232 , MSP430F5234 , MSP430F5237 , MSP430F5239 , MSP430F5242 , MSP430F5244 , MSP430F5247 , MSP430F5249 , MSP430F5252 , MSP430F5253 , MSP430F5254 , MSP430F5255 , MSP430F5256 , MSP430F5257 , MSP430F5258 , MSP430F5259 , MSP430F5304 , MSP430F5308 , MSP430F5309 , MSP430F5310 , MSP430F5324 , MSP430F5325 , MSP430F5326 , MSP430F5327 , MSP430F5328 , MSP430F5329 , MSP430F5333 , MSP430F5336 , MSP430F5338 , MSP430F5340 , MSP430F5341 , MSP430F5342 , MSP430F5418 , MSP430F5418A , MSP430F5419 , MSP430F5419A , MSP430F5435 , MSP430F5435A , MSP430F5436 , MSP430F5436A , MSP430F5437 , MSP430F5437A , MSP430F5438 , MSP430F5438A , MSP430F5500 , MSP430F5501 , MSP430F5502 , MSP430F5503 , MSP430F5504 , MSP430F5505 , MSP430F5506 , MSP430F5507 , MSP430F5508 , MSP430F5509 , MSP430F5510 , MSP430F5513 , MSP430F5514 , MSP430F5515 , MSP430F5517 , MSP430F5519 , MSP430F5521 , MSP430F5522 , MSP430F5524 , MSP430F5525 , MSP430F5526 , MSP430F5527 , MSP430F5528 , MSP430F5529 , MSP430F5630 , MSP430F5631 , MSP430F5632 , MSP430F5633 , MSP430F5634 , MSP430F5635 , MSP430F5636 , MSP430F5637 , MSP430F5638 , MSP430F6433 , MSP430F6435 , MSP430F6436 , MSP430F6438 , MSP430F6630 , MSP430F6631 , MSP430F6632 , MSP430F6633 , MSP430F6634 , MSP430F6635 , MSP430F6636 , MSP430F6637 , MSP430F6638 , MSP430F6720 , MSP430F6720A , MSP430F6721 , MSP430F6721A , MSP430F6723 , MSP430F6723A , MSP430F6724 , MSP430F6724A , MSP430F6725 , MSP430F6725A , MSP430F6726 , MSP430F6726A , MSP430F6730 , MSP430F6730A , MSP430F6731 , MSP430F6731A , MSP430F6733 , MSP430F6733A , MSP430F6734 , MSP430F6734A , MSP430F6735 , MSP430F6735A , MSP430F6736 , MSP430F6736A , MSP430F6745 , MSP430F67451 , MSP430F67451A , MSP430F6745A , MSP430F6746 , MSP430F67461 , MSP430F67461A , MSP430F6746A , MSP430F6747 , MSP430F67471 , MSP430F67471A , MSP430F6747A , MSP430F6748 , MSP430F67481 , MSP430F67481A , MSP430F6748A , MSP430F6749 , MSP430F67491 , MSP430F67491A , MSP430F6749A , MSP430F6765 , MSP430F67651 , MSP430F67651A , MSP430F6765A , MSP430F6766 , MSP430F67661 , MSP430F67661A , MSP430F6766A , MSP430F6767 , MSP430F67671 , MSP430F67671A , MSP430F6767A , MSP430F6768 , MSP430F67681 , MSP430F67681A , MSP430F6768A , MSP430F6769 , MSP430F67691 , MSP430F67691A , MSP430F6769A , MSP430F6775 , MSP430F67751 , MSP430F67751A , MSP430F6775A , MSP430F67761 , MSP430F67761A , MSP430F6776A , MSP430F67771 , MSP430F67771A , MSP430F6777A , MSP430F67781 , MSP430F67781A , MSP430F6778A , MSP430F67791 , MSP430F67791A , MSP430F6779A , MSP430FE423 , MSP430FE4232 , MSP430FE423A , MSP430FE4242 , MSP430FE425 , MSP430FE4252 , MSP430FE425A , MSP430FE427 , MSP430FE4272 , MSP430FE427A , MSP430FG4250 , MSP430FG4260 , MSP430FG4270 , MSP430FG437 , MSP430FG438 , MSP430FG439 , MSP430FG4616 , MSP430FG4617 , MSP430FG4618 , MSP430FG4619 , MSP430FG477 , MSP430FG478 , MSP430FG479 , MSP430FW423 , MSP430FW425 , MSP430FW427 , MSP430G2001 , MSP430G2101 , MSP430G2102 , MSP430G2111 , MSP430G2112 , MSP430G2121 , MSP430G2131 , MSP430G2132 , MSP430G2152 , MSP430G2201 , MSP430G2201-Q1 , MSP430G2211 , MSP430G2212 , MSP430G2221 , MSP430G2231 , MSP430G2231-Q1 , MSP430G2232 , MSP430G2252 , MSP430G2302 , MSP430G2312 , MSP430G2332 , MSP430G2352 , MSP430G2402 , MSP430G2432 , MSP430G2452 , MSP430L092

 

  1.   MSP430rep%#8482; 32-kHz Crystal Oscillators
    1.     Trademarks
    2. 1 The 32-kHz Crystal Oscillator
      1. 1.1 The Crystal
      2. 1.2 The Oscillator
    3. 2 Crystal Selection
      1. 2.1 Effective Load Capacitance
      2. 2.2 ESR Value
      3. 2.3 Tolerance
      4. 2.4 Start-up Time
    4. 3 PCB Design Considerations
    5. 4 Testing the Crystal Oscillator
      1. 4.1 Oscillator Frequency vs Load Capacitance
      2. 4.2 Negative Resistance Method
      3. 4.3 Relationship Between Crystal ESR and Safety Factor
    6. 5 Crystal Oscillator in Production
      1. 5.1 PCB Material, Quality, and Cleaning
      2. 5.2 Soldering and Contact Impedance
      3. 5.3 Environmental Influences, Temperature, and Humidity
      4. 5.4 Device-Specific Features to Support Better Start-up Behavior
    7. 6 Hardware Troubleshoot for Crystal-Oscillator Start-up in Production
    8. 7 References
  2.   Revision History

6 Hardware Troubleshoot for Crystal-Oscillator Start-up in Production

The purpose of this chapter is to provide a guideline for hardware troubleshooting when the 32-kHz crystal and MSP430 MCU LFXT oscillator do not work as expected in production. Specifically, when failures associated with slow starting or nonstarting crystal-oscillator circuits affect production yield.

Production start-up issues are divided into two categories. The first is simply crystal oscillators that will not start, and the second category is crystal oscillators that start slowly. This second category is a candidate for the XTS toggle method described in Section 5.4. The goal is to identify solutions that can improve the crystal-oscillator circuit. This improvement can be either a reduction in start-up time or changing the circuit from one that does not start to one that starts slowly. Before applying a solution, it is necessary to identify the issue that is preventing or delaying the start-up. To identify these issues, the following check points are recommended.

  1. Check Firmware. While outside of the scope of this discussion, the firmware should follow best practices as found in the MSP430 MCU family user's guides and code examples.
  2. Check the errata to determine if there are bugs related to LFXT and if the design violates the errata bugs.
    1. If errata number XOSC8 (ACLK failure when crystal ESR is below 40 kΩ) applies to the device (for instance, MSP430F4152), refer to XOSC8 Guidance for information regarding working with this erratum.
    2. If errata number XOSC7 (internal crystal load capacitance issue) applies to the device (for instance, MSP430F413), disable the internal crystal load capacitance.
  3. Check board design if the Crystal + LFXT circuit design follows the recommendations in Section 3.
  4. Check PCB cleanliness. If not clean, use an appropriate cleaning agent to clean it and test again.
  5. Check the safety factor, following the guidelines in Section 4.2.

Figure 13 shows a flow chart for troubleshooting to identify possible causes and corrective actions.

lfxt_troubleshooting_tree.gifFigure 13. LFXT Troubleshooting Decision Tree