Custom board for i.MX233 failed to boot

Started by Sharagim, July 04, 2018, 06:35:05 AM

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I tried to design a board but failed to boot. I trace the problem with u-boot debug and you can see the log below, in my trace I see writel(vddactrl, &power_regs->hw_power_vddactrl); is where that this problem happening.

HTLCSPL: Serial Console Initialised
SPL: Initialising Power Block
SPL: Switching CPU clock to 24MHz XTAL
SPL: Setting auto-restart bit
SPL: Setting VDDD 25mV below DC-DC converters
SPL: Setting VDDA 25mV below DC-DC converters
SPL: Setting VDDIO 25mV below DC-DC converters
SPL: Starting 5V input detection comparator
SPL: Starting battery voltage measurement logic
SPL: Initialisating LRADC
SPL: Enabling LRADC battery measurement
SPL: LRADC channel 7 is present - configuring
SPL: LRADC channel 7 configuration complete
SPL: Configuring power source
SPL: Using default DC-DC clocksource
SPL: Pre-Configuring power block
SPL: Battery Voltage = 2080mV
SPL: Battery Voltage = 2080mV
SPL: Battery Voltage = 4192mV
SPL: Battery Voltage too high
SPL: Configuring power block to boot from 5V input
SPL: 5V VDD good
SPL: Booting from 5V supply
SPL: Powering up 4P2 regulator
SPL: Configuring common 4P2 regulator params
SPL: Enabling 4P2 regulator
SPL: Charging 4P2 capacitor
SPL: Disabling 4P2 DC-DC Input
SPL: Setting 4P2 brownout level
SPL: Battery Voltage = 0mV
SPL: Switching DC-DC converters to 4P2
SPL: Enabling 4â–’HTLCSPL: Serial Console Initialised


You need some basic knowledge about electronic circuits and PCB layout before start something so complex.
What I spot on first sight is that you put thin tracks on your power supply lines, this may make PCB layout easier but is totally wrong.
Add copper ground planes, wire all power supplies with minimum 40 mils and generally find on the internet books about PCB design.
USB and Ethernet pairs should be routed as differential pairs with 90 ohm impedance, try to equalize RAM memory lines length as much as possible.

Google search bring these documents:

Good luck


Thanks for reply.
I tried to fix PDN but nothing happens and it stopped on the same line. For the RAM matching length as you can see I placed the RAM on bottom layer and tried to keep traces very short and but sure I will keep your words and try to fix it also.
In this case I think it is stopping to boot before RAM init and seems the problem is in some other points.