AM625: EMMC reset start abnormal

Ethan Tian

Intellectual 1872 points

Part Number: AM625
Other Parts Discussed in Thread: TPS65219

Hi experts

Issue Description:

After flashing the system to eMMC, the power-on boot starts normally;
Long press the PB pin of the TPS65219 causes the PMIC to power down and then press the PB pin of the TPS65219, also can boot normally
Normal start-up is also ok by pressing the reset button (pin F20 reset_REQz), and releasing the reset button after power-up.
Pressing the reset button (pin F20 reset_REQz) does not start up normally
Boot pin is configured as: 0000 0010 0100 1011
Change the boot method to TF card boot, boot pin configured as: 0000 0010 0100 0011, which looks like this:

The restart normally, either by pressing the reset key or by entering reset at UBoot
After the system boots, it cannot be restarted, regardless of the reboot or devmem2 0x44e00f00 w 1 command, and cannot reset by pressing the reset key.

The relevant SCH are as follows:

Debug Data:

Using the reset command in UBoot, it is stuck in the following interface

After the system is up, use the reboot command to get stuck in the following location

Using the devmem2 0x44e00f00 w 1 command, the result is as follows:

After pressing the reset key, the MMC0_CLK clock waveform is measured as follows. Pressing the reset key the initial clock waveform is the same as the power-up. start the dynamic frequency modulation and the system starts up normally; press the reset key and after the initial clock, the MMC0_CLK becomes a stable 25-MHz clock. the system does not boot.