I. Introduction
When the customer used the Xinchi X9U platform to build a smart cockpit product, they found that when the firmware was programmed, the USB device was not recognized by Windows when connected to the USB interface of the SSA through USB and was always in the Ready state.
2. SEMIDRIVE X9U does not recognize debugging points when plugged into USB
① It is recommended that customers measure the SoC's crystal clock 32.768KHz and 2 channels of 24MHz to see if the frequency is normal. The customer reported that 32.768KHz is normal, and the other 2 channels of 24MHz have no waveform output.
▲ Figure 1 SoC system clock circuit diagram
② Because there is no clock signal at 24MHz in the AP domain and SAFETY domain, check the SoC data sheet. Their power domains belong to VDDA_AP and VDDA_SAFETY respectively.
▲ Figure 2 The power domain where the SoC clock is located
③ It is recommended that the customer measures whether the power supply VDD_AP_DRAM_0V8 has a voltage output. It is found that VDD_AP_DRAM_0V8 has no voltage output and the EN1 signal PWR_CTRL0 of the test power supply U501 has a high output level.
▲ Figure 3 Schematic diagram of power supply U501
④ It is recommended that the customer measure whether the power supply VSFT_1V8 has a voltage output. It is found that VSFT_1V8 has no voltage output. The EN signal SYS_PWR_ON of the test power supply U400 has a high output level, and the performance is the same as that of U501 above.
▲ Figure 4 Schematic diagram of power supply U400
⑤ Ask the customer whether the power chip model has been changed. The customer feedback is that the original schematic reference design is directly used. Verify the BOM table of the original DEMO board and find that the model in the original schematic is not consistent with the actual BOM model. The principle The model number in Figure U501 is LP875610RNFTQ1, and the corresponding model number in the BOM table is LP875610BRNFRQ1. The U400 model in the schematic diagram is LP873200RHDTQ1, and the corresponding model in the BOM table is LP873248RHDRQ1. After confirmation with the original manufacturer, the power supply model in the BOM table, Ti, has been configured to the values required by the platform when it leaves the factory. There is no need for customers to change the settings through the I2C bus. .
▲ Figure 5 X9U power supply design description
⑥ The customer's power supply has no output because the power chip has not been programmed with OTP. This situation occurs mainly because the customer did not pay attention to confirm the BOM list of the DEMO board, and also did not send the schematic diagram for review, so some details were not obtained. Urgent correction. After the customer changed the power chip model, the power output was normal, the USB connection was normal, the firmware was programmed normally, and the problem was solved.
The above are the debugging points for SEMIDRIVE X9U not recognized when plugged into USB
Appendix: References
①《 SD008_X9U_MS_TI_B01_SCH 》
②《 SD008_X9U_MS_TI_B01_BOM 》
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