i.MX Processors中的主题 Re: Problem with i.MX28 ROM BOOT

Problem with i.MX28 ROM BOOT

Jan_E — Wed, 05 Nov 2014 11:01:55 GMT

Hi,

We just received a batch of first prototypes based on the i.MX28. The following happens at the debug-port:

0x80508002 ERROR_ROM_NAND_DRIVER_NO_NCB

0x80502008 ERROR_ROM_USB_CONNECT_TIMEOUT

(Repeats with some seconds interval)

It is not strange that the FLASH fails as it is empty and the USB0 is not connected at the time.

When we connect the USB0 to be able to flash our system Windows does not recognize it as an HID-device. (Happens in Linux too)

We did the same using the EVK and it works fine.

Noted was that the debug-info stopped when USB0 is connected.

We use external +5V (or USB if available) to power the PMU through the VDD5V but the voltage levels are a little strange:

VDDIO 3.155V

VDDA 1.797V

VDDD 1.175V

VDD4P2 0.838V

VDD1P5 0V

The first three are reasonable, but the VDD1P5 is not used and has only a 33uF capacitor connected. VDD4P2 seems odd too and is not used externally.

The PMU is configured according to the i.MX23 reference design with 5V only (no battery).

The DC/DC inductor is in place.

Current consumption is around 110mA@5V.

This has really put a stop for us and I would very much appreciate any help.

Thanks,

Jan

Re: Problem with i.MX28 ROM BOOT

igorpadykov — Wed, 05 Nov 2014 12:12:10 GMT

Hi Jan

processor behaviour greatly depends on fuses, so one can compare

fuses on i.MX28 EVK and custom board for example with OBDS fuse example

(can be run with jtag) and check sect.12.3.1 OTP eFuse Table 12-8. General ROM Bit MCIMX28RM

such as ENABLE_PIN_BOOT_CHECK fuse and others

one can also check p.15 imx28_evk_revD_sch.pdf boot selection and 24MHz crystal

IMX_OBDS : On-Board Diagnostic Suit for the i.MX28.

IMX28_EVK_DESIGN_FILES_R10 : i.MX28 EVK Design Files: Hardware Schematics

Regarding USB connection one needs to try Windows XP computer, probably try

different PCs.

Best regards

igor

Re: Problem with i.MX28 ROM BOOT

VladanJovanovic — Wed, 05 Nov 2014 12:36:18 GMT

Hi Jan,

please also check why those voltages are wrong. Something is pulling them down оr connection issue?

br,

Vladan

Re: Problem with i.MX28 ROM BOOT

Jan_E — Wed, 05 Nov 2014 12:37:13 GMT

Hi Igor,

Tahnk you for the answer.

The JTAG-pins are unfortunately not exposed on our design (the i.MX28 is straight from the box).

I have checked the 24MHz and it is running.

I will go on checking so no external power sources does anything stupid. There is an external regulator for the LAN transceiver but it is controlled by the VDDIO. I have also played around with the capacitors for the VDD4P2 with and without a resistor for the high capacity ones but nothing really helps.

Are there any good documentation on the exact behaviour of the PMU? I have already read the AN4199 but it is not very exact in how everything operates and what dependencies there are at boot time.

Thanks,

Jan

Re: Problem with i.MX28 ROM BOOT

Jan_E — Wed, 05 Nov 2014 12:41:38 GMT

Hi,

I see I got to you from two fronts :-). I asked the local Arrow FAE for help yesterday. I guess we can continue here.

The 4.2V is not loaded by anything other than the two 1k resistors per the i.MX233 reference design (connected to DCDC_BATT and BATT) and the 33uF. Measuring resistance when powered off is high impedance on both the 4.2V and 1.5V.

I understand some high currect event during power on can stop it from working properly. What do you suggest I start doing? Measuring voltage turn-on sequences?

Thanks,

Jan

Re: Problem with i.MX28 ROM BOOT

VladanJovanovic — Wed, 05 Nov 2014 12:50:09 GMT

Have you checked that soldering on the board is fine?

Voltage turn-on sequence is good to check and verify as well.

Vladan

Re: Problem with i.MX28 ROM BOOT

igorpadykov — Wed, 05 Nov 2014 12:57:27 GMT

Hi Jan

from log seems board is trying to boot from SD.

LCD_DATA0-3 should be low for USB boot.

LCD_RS needs to be pulled HIGH to enable Resistor Boot Mode.

if LCD_RS is pulled low, the i.MX28 will attempt to boot from OTP.

(p.15 imx28_evk_revD_sch.pdf).

Also one can try to put chip to recovery mode connecting PSWITCH

with 10 kΩ resistor to VDDIO (set PSWITCH HIGH LEVEL > 2.45V)

~igor

Re: Problem with i.MX28 ROM BOOT

Jan_E — Wed, 05 Nov 2014 12:59:44 GMT

Yes,

The soldering is good. We have tried multiple boards with the same symptoms.

According to the reference manual:

"When the voltage

rails have reached their target values, the digital logic reset is deasserted and the CPU begins

executing code."

As I get debug info, all voltages must have been at correct levels.

I'll get going checking the sequence.

/Jan

Re: Problem with i.MX28 ROM BOOT

Jan_E — Wed, 05 Nov 2014 13:00:43 GMT

Hi,

I have tried different boot modes with no change.

I thought it always reverted to the USB0 if all else failed?

Regards,

Jan

Re: Problem with i.MX28 ROM BOOT

Jan_E — Wed, 05 Nov 2014 14:59:14 GMT

Ok, just finished measuring.

The sequence is as follows:

- Power on 5V

- 1ms delay

- VDDIO (3.3V)

- 1ms

- VDDA (1.8V)

- 1ms

- VDDD (1.2V)

The 24MHz starts ~6ms after the 3.3V has turned on.

I also note a slight drop in the generated voltages ~5ms after they have stabilized.

To me the above seems reasonable. I don't really know where to go from here.

VDD 4.2V starts to rise at the same time as VDDIO but starts to drop slowly again after ~3ms. It never reaches more than ~0.8V.

Regards,

Jan

Re: Problem with i.MX28 ROM BOOT

igorpadykov — Wed, 05 Nov 2014 15:43:37 GMT

What Windows PC had you tried ?

Please try with Windows XP.

Also you can run any usb sniffer on PC and check

if there is USB connection to any port.

Actually bad contact (poor soldering) is most possible reason,

since ERROR_ROM_USB_CONNECT_TIMEOUT just

points that ROM can not see connection on USB line.

~igor

Re: Problem with i.MX28 ROM BOOT

jimmychan — Thu, 06 Nov 2014 03:44:31 GMT

What are the following pins connected to? Please double check the following pins are connected properly. For details, please read the Table in Special Signal Considerations in i.MX28 datasheet.

Re: Problem with i.MX28 ROM BOOT

Jan_E — Thu, 06 Nov 2014 07:35:02 GMT

Hi,

They are all connected per the table except DEBUG that is unconnected (freefloating).

What can cause the 4.2V to be unoperational but the VDDIO, VDDA and VDDD operational? From what I understand the only difference between them is the current limiter to the 4.2V. The DC/DC doesn't seem to work (from the lack of 4.2V?) so the voltages measured must be from the internal linear regulators that are supposedly weak but are enough to power the external memories leading me to believe there are at least no short cuts. The information on the PMU is however far from detailed so it is not easy to pin-point the source of my problems.

I'll start isolating the i.MX28 and see where that leads. Any further help is of course welcome!

Thanks,

Jan

Re: Problem with i.MX28 ROM BOOT

Jan_E — Thu, 06 Nov 2014 07:46:59 GMT

Hi,

It is a WIN7 64bit. I will dig up something with XP and try but as we have tested with another PC running Linux getting the same result I don't think it will help much.

As I wrote earlier, the debug prints are stopping when the USB is connected so I assume the i.MX28 is sensing that the cable is inserted. We have tried four boards with the exact same symptom but I will try a fifth.

What is the connection between the lack of 4.2V and no USB? It would be nice to have some better explanation of how the i.MX28 starts and turn off one or the other power source.

Thanks,

Jan

Re: Problem with i.MX28 ROM BOOT

igorpadykov — Thu, 06 Nov 2014 08:32:02 GMT

Hi Jan

what "4.2V" are you refering ? VDD4P2 is not turned on

by ROM it may be turned on (if used at all) later in bootlets.

Seems there were issues with USB 3.0 microsoft driver - it prevented

i.MX28 to be recognized as HID. If your PC has USB 3.0 please

upgrade it with all latest Windows patches.

~igor

Re: Problem with i.MX28 ROM BOOT

Jan_E — Thu, 06 Nov 2014 09:56:29 GMT

Hi,

I'm lazy so I didn't write VDD4P2 but that is the 4.2V I refer to. That information was very good, now I don't need to wonder why the DC/DC doesn't start nor why the VDD4P2 is ~0.8V.

I have tried the fifth board and a WINXP PC. No luck.

I have also measured the resistance to ground for the D+ and D- of USB0 and that indicates I have connection to the i.MX28 since the resistance is in the few Mohm range that you would expect from a non-powered pin. Not very scientific but it works :-)

Regards,

Jan

Re: Problem with i.MX28 ROM BOOT

igorpadykov — Thu, 06 Nov 2014 10:40:32 GMT

Hi Jan

you can check voltages on all power rails - are they smooth,

since brownout condition may lead to chip reset.

Important that C,R values on power rails were the same as on EVK, since

other may lead to LDO unstability. Other points of interest:

TESTMODE, PSWITCH, RESET.

Also one can try attaching external 5V supply to VDD5V and slightly

increase it to 5.2V.

~igor

Re: Problem with i.MX28 ROM BOOT

Jan_E — Thu, 06 Nov 2014 11:14:53 GMT

Hi,

They are all nice and clean. I cannot get to the TESTMODE as it is under the BGA. The capacitances per rail are 10nF+100nF+1uF+10uF+22uF but as the rails are clean I don't think they oscillate.

I tried increasing VDD5V but no change.

I checked the USB signals with a logic analyzer and there are some transitions during ~400ms after connected cable but no data that I can identify. Do you know what the initial hand-shake is supposed to be like?

Regards,

Jan

Re: Problem with i.MX28 ROM BOOT

igorpadykov — Thu, 06 Nov 2014 12:06:41 GMT

Shortly after cable connection (note first power i.MX28, then attach USB cable)

device is attached as below

http://www.beyondlogic.org/usbnutshell/usb2.shtml

then in about 10ms interval you should see impulses on both D-,D+

(chirp), followed idle state.

~igor

Re: Problem with i.MX28 ROM BOOT

Jan_E — Thu, 06 Nov 2014 14:32:10 GMT

Hi,

The D+ and D- are idling high when nothing is connected. That is according to the RM for i.MX28. When the cable is connected, D- pulses low and in the middle of that pulse D+ goes low and stay there after some extra short pulses. It then idle with D- high and D+ low. (I cannot sample higher than 25MHz so I might miss some data.)

I also got information from the board manufacturer that the boards have been x-rayed to ensure good soldering of the BGA so it is not a soldering issue.

This is really odd. As the i.MX28 cannot find an application in the flash it should go over to USB0. As the voltages, clock etc are OK and it does send debug info, I cannot see why the USB shouldn't work. D+ and D- go straight into the USB cable without any other components involved (except the connector) with very short traces routed next to each other.

Any more ideas what to try?

Regards,

Jan