troubleshooting of produced prototype: nrf9160

[David]

Hello,

I have developed 10pcs of one prototype with the nrf9160 SiP. 

I have some questions regarding some errors im having.

Regarding the SIM 1V8 driver VCC, for UICC interface, I am observing a fluctuation on this channel/voltage, from 0V -> 0.4 VDC, with approximately 1hz frequency.

What can cause this to happend, what is the normal behaviour of this channel when it is short-circuited with ground or something else/similar ?

My second question is regarding the attached image, im observing this on a few of my prototypes, im not able to upload any modem firmware to the SiP, any idea why?

Regards,

David

[Didrik Rokhaug]

Hi.

As the problem only occurs on some of your boards, I suspect there is a HW problem.

If you can share some schematics, I will try to find someone that can look at them to see if there is anything wrong.

Best regards,

Didrik

[David]

[Didrik Rokhaug]

Could you also share the rest of your schematics?

It is very limited what we can do with what you provided.

[Didrik Rokhaug]

Hi, and sorry for the long wait.

I have talked to one of our hardware experts, and there are some differences between your design and our reference designs:

You are missing a 47uF capacitor on IO_supplyu/DEC0.

The recommended value for the DEC0 decoupling capacitor has been increased to 47 uF. This is done to improve low-frequency clock accuracy which improves protocol robustness in lower limit temperature conditions. No issues have been observed in practical use on boards with lower values, but 47 uF is expected to perform better over conditions and production variation.

When it comes to your SIM interface, the differences between your SIM interface and ours is that C17 = 1uF instead of 100nF and C16 = 1uF instead of 10nF.

Do these changes solve your problem?

Best regards,

Didrik

[David]

Hey Didrik,

Thank you for the reply. I will have a closer look at what you commented, about the hardware.

First I have to solve the application FW/SW for the prototype, maybe you have help me answer me on some troubles I have been having?

So, Im using the PCA10090 for reference.

I've set-up the Segger embedded environment correctly, and installed west with the latest repositories, v1.1.0.

I have managed to create a FW which I can upload over SWD to reference board, this works. This works both with .elf and merged.hex (non-secure) and (secure).

If I try to upload this to my prototype, it will not work with merged.hex, it only works when I build without "ns", as .elf.

 -----

I've read up on the SPM, and for everything to work, I have to first upload the SPM firmware without "ns", then I have to upload my application firmware, as "ns".

Also, I have to set in proj.conf, CONFIG_SPM=n for this to be available as .elf, for me to build. If not, this wont work.

-----

Ideally, I would like to use the refernece board for prototyping, so that this can be 100% compatible with my prototype, as-far as code compatibility, as multiple image file (merged.hex). 

How can I achieve this?

Im not very experience with Zephyr yet, and trying to learn.

I'd appreciate a fast response.

In advance, thank you.

below is project files.

Regards, David

CONFIG_BSD_LIBRARY=y
CONFIG_GPIO=y
CONFIG_SERIAL=n
CONFIG_STDOUT_CONSOLE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_TEST_RANDOM_GENERATOR=y
CONFIG_NETWORKING=y
CONFIG_NET_BUF_USER_DATA_SIZE=1
CONFIG_NET_SOCKETS_OFFLOAD=y
CONFIG_NET_SOCKETS=y
CONFIG_NET_SOCKETS_POSIX_NAMES=y
CONFIG_NET_RAW_MODE=y
CONFIG_TRUSTED_EXECUTION_NONSECURE=y
CONFIG_LOG=n
CONFIG_LOG_DEFAULT_LEVEL=4
CONFIG_HEAP_MEM_POOL_SIZE=1024
# LTE link control
CONFIG_LTE_LINK_CONTROL=y
CONFIG_ADC=y
CONFIG_ADC_0=y
CONFIG_ADC_NRFX_SAADC=y
CONFIG_MAIN_STACK_SIZE=4096
CONFIG_SPM=n