AM3352: BOOT item settings when using PMIC RTC

Guru 10355 points
Part Number: AM3352

Tool/software:

Hi,

The CPU is AM3352 and the PMIC is TP65910AA1RSL(R). To reduce system costs, we are considering reducing the number of RTC-ICs on the custom board and trying out PMIC RTC. I would like to inquire about the PMIC BOOT pin settings. When using PMIC RTC, a 32K clock is required.

① Connect a 32kHz crystal oscillator between OSC32KIN-OUT
② Connect a 32kHz oscillator resistor to OSC32KIN

Whether ① or ② is required is determined by the BOOT settings according to the data sheet. Until now, BOOT1,0 = 1,0 (EEPROM sequence) has been set for custom boards. When using PMIC RTC with AM3352 and DDR2, how should the BOOT pins be set? Is it okay to keep it as before with BOOT1,0 = 1,0? If it is okay to leave BOOT1,0=1,0 (EEPROM sequence), which one will be selected, ① or ②?

Thanks,

Conor

  • Hi Conor, 

    For the EEPROM sequence with the AM3352, the clock source is the internal RC oscillator.
    This information for the application of the BOOT1,0 = 1,0 (EEPROM sequence), is found in the TPS65910Ax User Guide for TPS65910Ax.

    With the internal RC oscillator, the connections should actually follow a third configuration,
    with OSC32KIN connected to GND and OSC32KOUT floating.

    Hope this helps. Let me know if further clarification is needed.

    Best Regards, 
    Sarah