topic Re: IMXRT1064 serial boot in i.MX Processors

IMXRT1064 serial boot

mike_asm — Thu, 29 Jun 2023 15:47:15 GMT

Hi NXP Community,

we use i.MX for several projects. Initially we would like to load our devices via USB (serial mode). The boards that have an IMXRT1170 (3 different projects) work without problems. The boards with IMXRT1064 (2 projects) can boot from flash, but USB is not recognized, an error occurs (Unknown USB Device (Device Descriptor Request Failed)). The HW design of USB interface, boot switches, PoR is the same. The example project "hello-world" also runs. If we erase the chip with the "EnableEraseAllFlashBanks" flag, the USB device reports as expected, but after the reset or trying to connect comes the error again.
What is the difference between IMXRT1170 and IMXRT1064 at the point? What do we have to observe to get a USB connection for serial boot?

Re: IMXRT1064 serial boot

diego_charles — Thu, 29 Jun 2023 18:44:41 GMT

Hi @mike_asm

I hope you are doing well.

Please correct me if I my understanding is not correct.

I understand that you are using the i.MX RT1064 serial downloader mode, over USB1 pins, to update application images. Also, that after an erase there is a successful USB1 enumeration. But, after a reset or power cycle, USB1 can not longer enumerate.

To double check USB enumeration, while on serial downloader mode you can use our SDPHOST tool (command line tool) to check for the presence of the bootROM. Here is an example.

sdphost -u 0x1FC9,0x0130 -j -- error-status

The SDPHOST tool is already integrated by the MCUXpresso Secure Provisioning tool (GUI tool). So there is a button in the tool to check connection over USB or UART, this way you can avoid having to write a command like above.

To check that the MCU is serial downloader mode, you can check the address of the program counter (PC ). The PC can be read over SWD/JTAG. SWD is used by default. If the address is something like 0x2xxxx the MCU is probably in serial downlader mode. Also, if you have UART1 pins routed you can make a ping to the ROM bootloader to verify.

As a note, to enter into serial downloader mode the boot mode pins should be set to 0b01 before releasing reset. Did you made this setting?

All the best,

Diego.

Re: IMXRT1064 serial boot

mike_asm — Fri, 30 Jun 2023 15:05:35 GMT

Hi Diego,

Thank you for your quick response.

In this case, unfortunately, we cannot use SDPHOST tool because the USB descriptor is corrupted, the Vendor Id and Device Id are incorrect, and no connection is established.

After reset, the MCU is probably in serial downloader mode (address 0x2xxxxx) in a loop. The good case and bad case addresses are different.

So as assume this is a loop in error handler.

Is there a method to determine what is causing the error? Thanks.

Re: IMXRT1064 serial boot

mike_asm — Fri, 30 Jun 2023 15:06:21 GMT

Hi Diego,
Thank you for your quick response.
In this case, unfortunately, we cannot use SDPHOST tool because the USB descriptor is corrupted, the Vendor Id and Device Id are incorrect, and no connection is established.
After reset, the MCU is probably in serial downloader mode (address 0x2xxxxx) in a loop. The good case and bad case addresses are different.
So as assume this is a loop in error handler.
Is there a method to determine what is causing the error? Thanks.

Re: IMXRT1064 serial boot

diego_charles — Fri, 30 Jun 2023 16:45:20 GMT

Hi @mike_asm

Thank you for your response as well.

Please try to do a ping using UART1 pins. Lets check if the MCU is actually entering in serial downloader mode.

Diego

Re: IMXRT1064 serial boot

mike_asm — Fri, 07 Jul 2023 08:05:33 GMT

Hi Diego,
thanks for the suggestion. We'll try that. I'll let you know when we're so far.

Re: IMXRT1064 serial boot

mike_asm — Tue, 11 Jul 2023 06:42:33 GMT

Hi Diego,

we checked and yes, the MCU is in serial downloader mode. How can we switch to USB? What do we have to keep in mind?

We would like to use USB as a virtual COM port later. Thanks

Re: IMXRT1064 serial boot

diego_charles — Tue, 11 Jul 2023 14:50:40 GMT

Hi @mike_asm

Thanks for your reply,

Quick question, if you flash one of our USB demos from the SDK, does the USB ennumerates properly?

If not, maybe we are facing an HW issue.

All the best,

Diego

Re: IMXRT1064 serial boot

mike_asm — Tue, 11 Jul 2023 15:19:52 GMT

Hello Diego,
if we try your example evkmimxrt1064_hello_world_virtual_com, USB enumeration works fine. 
Even if we erase all flash banks, it works properly.

I also suspect a HW problem (e.g. some OTG pins). But the same design works at IMXRT1170.

What should we set to get the USB enumeration running?

Re: IMXRT1064 serial boot

diego_charles — Tue, 11 Jul 2023 16:27:38 GMT

thanks for letting me know @mike_asm

Would be possible that you share a bit from your schematic? I want to see USB connection and MCU supply rails. If you can not share publicly, we can create an internal case for this.

All the best,

Diego

Re: IMXRT1064 serial boot

mike_asm — Wed, 12 Jul 2023 13:31:57 GMT

Hi Diego, here is a part of our schematic. Thanks.

Re: IMXRT1064 serial boot

diego_charles — Wed, 02 Aug 2023 18:47:29 GMT

Hi @mike_asm

Let me make a follow up to the thread. After this time, did you found any other result ?

I saw that you are missing a capacitor for the VDD_SNVS_CAP. You need to have one 22 μ F² and a1 × 4.7 μF capacitor.

I also noted that you are not using the external 32 KHz crystal. Could rework your design to ensure to have the 32 KHz signal? I just want to make sure that it is not affecting the USB serial downloader ennumeration.

Thanks a lot for your patience.

Diego

Re: IMXRT1064 serial boot

mike_asm — Wed, 16 Aug 2023 15:39:12 GMT

Hi Diego, is something wrong in our design? Thanks.

Re: IMXRT1064 serial boot

diego_charles — Wed, 16 Aug 2023 18:21:35 GMT

Hi @mike_asm

Thank you for your reply!

I only saw that you are missing a capacitor, and suggested doing a little re-work to add the external 32 KHz cristal. Also a 32 KHz signal could be added, that mentioned as bypass mode in the RM. I am not sure if that will have an impact to solve the issue but it is convenient to test to narrow down.

https://community.nxp.com/t5/i-MX-Processors/IMXRT1064-serial-boot/m-p/1697922/highlight/true#M210154

Let me know if you have seen anything else.

Diego

Re: IMXRT1064 serial boot

mike_asm — Thu, 17 Aug 2023 07:31:29 GMT

Hi Diego, I think, that is a mistake in your Hardware Development Guide. We have 0,22µF capacitor, like on Evaluation Board. We don't use RTC in this project, therefor 32 KHz cristal is not populated. The same design with IMXRT1170 works without any problem in USB-Boot mode.

Is there some specific things else, have an impact to come in COM-Boot mode instead of USB-Boot mode?

Thank you.

Re: IMXRT1064 serial boot

diego_charles — Thu, 17 Aug 2023 21:17:37 GMT

Hi @mike_asm

Thank you for your reply!

The 4.7 uF is recommended as a bulk capacitor, while the 0.22uF as a decoupling cap. Unfortunately, sometimes the EVK does not strictly comply the hardware design guide recommendations, as the EVK is designed to be a low-cost development board. I will try to give with more information on this.

Eventougth your application still does not require the external 32 KHz, like for RTC. I cannot assure that the application will work properly without the crystal. This is because the external 32 KHz crystal signal (CKIL) can also be used by other peripherals, like WDOG, USB (in the wakeup scenario)

Currently, I do not know the specific reason to explain why your design can not enumerate the USB1 in serial downloader. For now, and before doing any other HW rework/investigation, the easiest test we could do is: calling the runBootloader() API.

I can make this work in our RT1064-EVK : the MCU gets into serial downloader mode and USB1 one gets enumerated. We now that the USB demos work on your board, so lets narrow down by invoking the roomBotloader during application execution.

/* * Copyright 2019 NXP * All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ #include "pin_mux.h" #include "clock_config.h" #include "board.h" #include "system_MIMXRT1064.h" #include "fsl_romapi.h" #include "fsl_wdog.h" #include "fsl_rtwdog.h" typedef struct { void (*RTWDOG_GetDefaultConfig)(rtwdog_config_t *config); void (*RTWDOG_Init)(RTWDOG_Type *base, const rtwdog_config_t *config); void (*RTWDOG_Deinit)(RTWDOG_Type *base); void (*RTWDOG_Enable)(RTWDOG_Type *base); void (*RTWDOG_Disable)(RTWDOG_Type *base); void (*RTWDOG_EnableInterrupts)(RTWDOG_Type *base, uint32_t mask); void (*RTWDOG_DisableInterrupts)(RTWDOG_Type *base, uint32_t mask); uint32_t (*RTWDOG_GetStatusFlags)(RTWDOG_Type *base); void (*RTWDOG_ClearStatusFlags)(RTWDOG_Type *base, uint32_t mask); void (*RTWDOG_SetTimeoutValue)(RTWDOG_Type *base, uint16_t timeoutCount); void (*RTWDOG_SetWindowValue)(RTWDOG_Type *base, uint16_t windowValue); void (*RTWDOG_Unlock)(RTWDOG_Type *base); void (*RTWDOG_Refresh)(RTWDOG_Type *base); uint16_t (*RTWDOG_GetCounterValue)(RTWDOG_Type *base); } rtwdog_driver_interface_t; /******************************************************************************* * Definitions ******************************************************************************/ #define EXAMPLE_LED_GPIO BOARD_USER_LED_GPIO #define EXAMPLE_LED_GPIO_PIN BOARD_USER_LED_PIN /******************************************************************************* * Prototypes ******************************************************************************/ /******************************************************************************* * Variables ******************************************************************************/ volatile uint32_t g_systickCounter; /* The PIN status */ volatile bool g_pinSet = false; /******************************************************************************* * Code ******************************************************************************/ void SysTick_Handler(void) { if (g_systickCounter != 0U) { g_systickCounter--; } } void SysTick_DelayTicks(uint32_t n) { g_systickCounter = n; while (g_systickCounter != 0U) { } } typedef struct { uint32_t version; status_t (*init)(uint32_t instance, flexspi_nor_config_t *config); status_t (*program)(uint32_t instance, flexspi_nor_config_t *config, uint32_t dst_addr, const uint32_t *src); status_t (*erase_all)(uint32_t instance, flexspi_nor_config_t *config); status_t (*erase)(uint32_t instance, flexspi_nor_config_t *config, uint32_t start, uint32_t lengthInBytes); status_t (*read)( uint32_t instance, flexspi_nor_config_t *config, uint32_t *dst, uint32_t addr, uint32_t lengthInBytes); void (*clear_cache)(uint32_t instance); status_t (*xfer)(uint32_t instance, flexspi_xfer_t *xfer); status_t (*update_lut)(uint32_t instance, uint32_t seqIndex, const uint32_t *lutBase, uint32_t seqNumber); status_t (*get_config)(uint32_t instance, flexspi_nor_config_t *config, serial_nor_config_option_t *option); } flexspi_nor_driver_interface_t; typedef struct { void (*WDOG_GetDefaultConfig)(wdog_config_t *config); void (*WDOG_Init)(WDOG_Type *base, const wdog_config_t *config); void (*WDOG_Deinit)(WDOG_Type *base); void (*WDOG_Enable)(WDOG_Type *base); void (*WDOG_Disable)(WDOG_Type *base); void (*WDOG_EnableInterrupts)(WDOG_Type *base, uint16_t mask); uint16_t (*WDOG_GetStatusFlags)(WDOG_Type *base); void (*WDOG_ClearInterruptStatus)(WDOG_Type *base, uint16_t mask); void (*WDOG_SetTimeoutValue)(WDOG_Type *base, uint16_t timeoutCount); void (*WDOG_SetInterrputTimeoutValue)(WDOG_Type *base, uint16_t timeoutCount); void (*WDOG_DisablePowerDownEnable)(WDOG_Type *base); void (*WDOG_Refresh)(WDOG_Type *base); } wdog_driver_interface_t; typedef struct { const uint32_t version; //!< Bootloader version number const char *copyright; //!< Bootloader Copyright void (*runBootloader)(void *arg); //!< Function to start the bootloader executing const uint32_t *reserved0; //!< Reserved const flexspi_nor_driver_interface_t *flexSpiNorDriver; //!< FlexSPI NOR Flash API const uint32_t *reserved1; //!< Reserved const rtwdog_driver_interface_t *rtwdogDriver; const wdog_driver_interface_t *wdogDriver; const uint32_t *reserved2; } bootloader_api_entry_t; #define g_bootloaderTree (*(bootloader_api_entry_t**)(0x0020001c)) void runBootloader(void* arg) { g_bootloaderTree-> runBootloader(arg); } /*! * @brief Main function */ int main(void) { /* Board pin init */ BOARD_ConfigMPU(); BOARD_InitBootPins(); BOARD_InitBootClocks(); /* Update the core clock */ SystemCoreClockUpdate(); /* Set systick reload value to generate 1ms interrupt */ if (SysTick_Config(SystemCoreClock / 1000U)) { while (1) { } } uint32_t arg = 0xeb100000; runBootloader (&arg); while (1) { /* Delay 1000 ms */ SysTick_DelayTicks(1000U); if (g_pinSet) { GPIO_PinWrite(EXAMPLE_LED_GPIO, EXAMPLE_LED_GPIO_PIN, 0U); g_pinSet = false; } else { GPIO_PinWrite(EXAMPLE_LED_GPIO, EXAMPLE_LED_GPIO_PIN, 1U); g_pinSet = true; } } }

Re: IMXRT1064 serial boot

mike_asm — Fri, 18 Aug 2023 09:21:43 GMT

Hi Diego,

Thank you for your reply!

We tried to call the runBootloader() API and we got USB1 enumerated.

We also get the USB enumeration if we erase the memory with the flag „Enable Erase All Flash Banks“.

But in this case the communication is broken when we try to send something.

Shall we try to do some HW reworking, quartz assembly?

Many thanks!

Re: IMXRT1064 serial boot

diego_charles — Wed, 23 Aug 2023 00:03:21 GMT

Hi @mike_asm

Thank you for letting me know! I think we are narrowing this! Let me summarize our findings. Please add anything.

Issue:

After a POR, serial downloader communication over USB is not working okay. Device is not being ennumerated properly.

Facts:

After a POR, serial downloader communication over UART is successful.
We are able to re-invoke the bootloader, and get serial downloader communication over USB
If you do an erase the bootloader gets called. Which is expected, as the boot ROM did not find any image to boot.

Given the above summary, I suggest:

Investigate the power-up sequence. Monitor and measure the timings for rails to be stable.
Do a little re-work to add the 32 KHz oscillator, or external signal.

All the best,

Diego

Re: IMXRT1064 serial boot

diego_charles — Sun, 17 Sep 2023 22:14:53 GMT

Hi @mike_asm

I hope you are doing great, just making a follow up to this topic.

Where you able to find the cause of the issue? Or did you find any issues with Power up sequence?

All the best,

Diego

Re: IMXRT1064 serial boot

mike_asm — Mon, 18 Sep 2023 07:30:53 GMT

Hello Diego, unfortunately not yet. Power up sequence looks good. In our design it is difficult to add a 32kHz oscillator and our HW developers don't think that will help. We will take this into account in the next project or when redesigning.