OSD3358 on custom board resets every 15s

[boscoe]

Hi all,

I have created a custom board with the OSD3358 BSM based on the PocketBeagle PCB. I can boot the processor with the OSD3358-SM-RED Linux image with the U-Boot patch as described here. The board boots, the LEDs flash and I get the output on the console as below. The first time it tries to boot I get to the ‘Starting Kernal’ where I see the current draw on my bench PSU drop and rise again as the boot process starts once more. If I enter the U Boot console to stop the normal boot process the same with happens. I’ve measured the cycle to ~15s. I have used the multi meter to verify the PMIC_GOOD/PWRONRESET (tied together) signal as well as the WARMRSTN signal going low as the boot process stops. I have measured all of the power supplies and they are fine.

Does anyone have any ideas on what might happening/ what I can check next?

Thanks.

U-Boot SPL 2018.01-dirty (Mar 29 2019 - 21:25:53)
Trying to boot from MMC1


U-Boot 2018.01-dirty (Mar 29 2019 - 21:25:53 +0000)

CPU  : AM335X-GP rev 2.1
I2C:   ready
DRAM:  512 MiB
No match for driver 'omap_hsmmc'
No match for driver 'omap_hsmmc'
Some drivers were not found
Reset Source: Power-on reset has occurred.
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
Using default environment

 not set. Validating first E-fuse MAC
BeagleBone: cape eeprom: i2c_probe: 0x54:
BeagleBone: cape eeprom: i2c_probe: 0x55:
BeagleBone: cape eeprom: i2c_probe: 0x56:
BeagleBone: cape eeprom: i2c_probe: 0x57:
Net:   usb_ether
Press SPACE to abort autoboot in 2 seconds
board_name=[A335BLNK] ...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
** Bad device 0:2 0x82000000 **
** Bad device 0:2 0x82000000 **
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
gpio: pin 56 (gpio 56) value is 0
gpio: pin 55 (gpio 55) value is 0
gpio: pin 54 (gpio 54) value is 0
gpio: pin 53 (gpio 53) value is 1
switch to partitions #0, OK
mmc0 is current device
gpio: pin 54 (gpio 54) value is 1
Checking for: /uEnv.txt ...
Checking for: /boot.scr ...
Checking for: /boot/boot.scr ...
Checking for: /boot/uEnv.txt ...
gpio: pin 55 (gpio 55) value is 1
2068 bytes read in 46 ms (43 KiB/s)
Loaded environment from /boot/uEnv.txt
debug: [dtb=osd3358-bsm-refdesign.dtb] ...
Using: dtb=osd3358-bsm-refdesign.dtb ...
Checking if uname_r is set in /boot/uEnv.txt...
gpio: pin 56 (gpio 56) value is 1
Running uname_boot ...
loading /boot/vmlinuz-4.9.45-ti-r57 ...
9464664 bytes read in 806 ms (11.2 MiB/s)
loading /boot/dtbs/4.9.45-ti-r57/osd3358-bsm-refdesign.dtb ...
64053 bytes read in 162 ms (385.7 KiB/s)
uboot_overlays: [fdt_buffer=0x60000] ...
uboot_overlays: loading /lib/firmware/AM335X-PRU-UIO-00A0.dtbo ...
853 bytes read in 117 ms (6.8 KiB/s)
loading /boot/initrd.img-4.9.45-ti-r57 ...
5908180 bytes read in 522 ms (10.8 MiB/s)
debug: [console=ttyO0,115200n8 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet] ...
debug: [bootz 0x82000000 0x88080000:5a26d4 88000000] ...
## Flattened Device Tree blob at 88000000
   Booting using the fdt blob at 0x88000000
   Loading Ramdisk to 8fa5d000, end 8ffff6d4 ... OK
   reserving fdt memory region: addr=88000000 size=70000
   Loading Device Tree to 8f9ea000, end 8fa5cfff ... OK

Starting kernel ...

 

[Neeraj Dantu]

Hi boscoe,

Please check for shorts on IO signals of the board. Also measure the total current consumption and compare it to the expected current consumption of an equivalent design such as a Beaglebone. Monitor the thermal behavior of the board as well as that would indicate an abnormal power draw as well. A high power draw on one of the power rails could be causing the board to reset periodically. Also make sure that PMIC_PB_IN pin of OSD335x is not grounded as that causes the PMIC to power cycle(every 8 sec).

Apart from shorting/current draw there might be a specific component at fault. The processor has already booted at ~15 seconds, are there other components that are being powered up/initialized at ~15 seconds?

Plotting the main power rails including the power input, the PMIC/processor interface and power rails of various subsystems of the processor with an oscilloscope might be useful to pin point which power rail is at fault if that is the case.

Hope that helps. Please let us know how it goes.

Neeraj

[Author]

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