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TPIC7218-Q1: TPIC7218 - 0x1B Register Allocation Fail

Prodigy 110 points

Replies: 4

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Part Number: TPIC7218-Q1

Our ABS product using TPIC7218 chip, found in the actual car matching 7218 chip initialization is not normal, that is, the control register (0x1B) of the 7218 chip is not configured successfully; the SPI of the MCU and 7218 chip is included in the accessory. Communication waveform and analytical data   


The SPI waveform when the MCU is properly configured with the TPIC7218:
The signal types from top to bottom are: CS, SCLK, MOSI, MISO.
As can be seen from the figure, the MCU assigns "7C" to the 0x1B register of the 7218 chip, and the 7218 chip returns the register address "1B" normally.
The signal types from top to bottom are: CS, SCLK, MOSI, MISO.
It can be seen from the figure that when the MCU assigns "00" and "7C" to the 0x10 and 0x1B registers of the 7218 chip, the 7218 chip does not return the register address "10" or "1B" normally, that is, the data is not normally written. The ECU's alarm cause type is related to the value of the "0x1B" control register.
  • Hi,

    Will notify your question to expert in early of next week.



  • In reply to Shinya Morita:


    Comparing "Properly configured(Top)" and "failed (Bottom), signal voltage high level from MCU looks different. This could be related to issue.

    My another suggestion is customer will define whether this is TPIC7218 issue or thier MCU/System/PCB related issue. One of  way is to swap the TPIC7218 between good PCB/System and failure system/PCB.



  • In reply to Shinya Morita:

    Hello Shinya,

    Thanks for your reply and suggestion! But now I have some further quesions as follows:

    1. Although the signal high level from MCU(MOSI) is lower than "Properly configured" case, the high level voltage is higher than "VIH_5V" electrical property parameter from the Datasheet of TPIC7218. So the signal high level voltage from MCU(MOSI) may be OK. And according to the results of the other 13 control registers, the signal high level voltage reduced does not affect the TPIC7218.

    2. From the another SPI waveform of the same "Failed configured" case, we find that the signal high level from MCU(MOSI) is same as the CS and SCLK signals, but the signal low level of the 0x1B register is higher than the other data bits. In this case, the reason for "Failed configured" case may be the EMC issue. However, why does it only affect the 0x1B register? The SPI communication frequency is 4MHz.

    Hope for your reply!

    Best regards

    Yantao Zheng

  • In reply to Yantao Zheng:


    Let me suggest two approaches.

    1) If this issue does not happen in all units and only a few units shows issue (or happened in mass production factory line), I suggest to treat this as part failure issue. Please contact to TI Sales team for further procedure for failure analysis. ABA swap test could be first step to do.(remove TPIC7218 from failure system board and put fresh part on it. And put removed part from failure system into good system board. Then see the issue is caused by parts or system.) 

    2) If this issue happens in new development stage in new platform and all units shows same issue, I would recommend to take zoon in waveform picture of SPI for both good and failure. I believe MCU is supposed to send stable voltage level signals all the time. If sometimes MCU provide lower level of signal, it should be something wrong in MCU or SPI signal line or system.

    And I suggest that customer make the voltage level stable and see if they still have issue or not.