i.MX ProcessorsのトピックRe: iMX6: how to trigger software reset

iMX6: how to trigger software reset

rafalwegner — Fri, 10 May 2013 11:52:48 GMT

Hello

Does anyone knows and could describe the procedure of how to trigger a reset of the board (power off / power on) from software (u-boot application)?

I believe some of the SRC registers should be configured properly to obtain such behaviour.

Thanks very much in advance

BR, Rafal

Re: iMX6: how to trigger software reset

AnsonHuang — Mon, 13 May 2013 05:54:48 GMT

Hi, Rafal

Do you mean the command of uboot to reboot the board? If yes, you can use "reset" command in uboot to reboot system, the eventual operation of "reset" command will trigger a wdog reset which will reboot i.MX6 SOC. But it will not reset the PMIC, so it is not a power off/on reset, it only reset our i.MX6 SOC.

If you use "reboot" command in kernel, the PMIC(PFuze) will be also reset by our wdog reset, which will be a power off/on reset.

So, in a word, in uboot, "reset" is to only reset our i.MX6 SOC, in kernel, "reboot" will reset both our i.MX6 SOC and external PMIC which connect its reset pin to our WDOG_B pin.

Re: iMX6: how to trigger software reset

rafalwegner — Mon, 13 May 2013 11:13:15 GMT

Hello

Thanks for your answer but what I actually would like to do is to reset the i.MX6 SOC from standalone program run in u-boot. From within this standalone program I would like to have the same behaviour (reset of iMX6) as user can trigger by running "reset" command in u-boot prompt.

Do you know how to trigger a wdog reset using internal iMX6 registers? Those settings of registers are what I am looking for.

BR, Rafal

Re: iMX6: how to trigger software reset

AnsonHuang — Mon, 13 May 2013 12:58:40 GMT

Hi，Rafal

Sorry for taking your question in wrong way, below are the answers:

To trigger wdog reset, you can write 0x4 to wdog's control register, it's address should be 0x21bc000, it is a 16 bits register, you need to write it in 16 bits access.

For SRC register, bit 0 of SRC_SCR register is to control whether you want a warm reset of cold reset of system. It's address should be 0x20d8000.

Please try it and let me know the result, thanks.

Re: iMX6: how to trigger software reset

rafalwegner — Mon, 13 May 2013 15:24:10 GMT

Thanks very much for your input. I am working on iMX6 DualLite processor and to trigger wdog reset I had to clear fourth bit of WDOG1_WCR register (0x020bc000). Now my program works as I needed.

Best Regards

Rafal

Re: iMX6: how to trigger software reset

zlhuang — Thu, 27 Mar 2014 05:49:51 GMT

Dear Yongcai,

I have several boards of the same hardware based on mx6dl-sabresd.

When I use "reset" command in u-boot, some boards reset from [WDOG ], but others always reset from [POR ].

I have no idea how to debug and fix it. Could you give your opinion?

Thanks.

BRs,

Re: iMX6: how to trigger software reset

AnsonHuang — Thu, 27 Mar 2014 07:39:32 GMT

Hi, ZL

Because in uboot, we only trigger wdog reset, and in kernel, when wdog reset, we enable it to output a wdog_b signal which will be connected to PMIC, and cause the whole board power down and power up again, that is why you get POR reset in kernel, but get WDOG in uboot.

Re: iMX6: how to trigger software reset

zlhuang — Thu, 27 Mar 2014 07:47:50 GMT

Dear Yongcai,

I got [POR ] after using "reset" command in u-boot on some of my boards

Is this reasonable? Or it's hardware issue?

Thanks.

BRs,

ZL.

Re: iMX6: how to trigger software reset

AnsonHuang — Thu, 27 Mar 2014 07:51:07 GMT

You can monitor the POR pin on i.MX6, the only reason of getting POR reset reason of that there is toggling on this pin.

Re: iMX6: how to trigger software reset

zlhuang — Thu, 27 Mar 2014 08:34:31 GMT

Thanks, Yongcai.

Do you mean it's the hardware circuit issue?

I will monitor the POR pin and report the result.

Re: iMX6: how to trigger software reset

zlhuang — Fri, 28 Mar 2014 08:12:30 GMT

Dear Yongcai,

Our board config WDOG2 to be the output (MX6DL_PAD_GPIO_1__WDOG2_WDOG_B) and connects it to POR.

When I config WDOG1 to generate wdog_reset, I measured that the WDOG_B is also asserted.

That's why the reset reason is POR.

Could you help? Thanks.

BRs,

Re: iMX6: how to trigger software reset

AnsonHuang — Fri, 28 Mar 2014 10:05:26 GMT

You can just disable the wdog_b signal when you config wdog1 to reset.

Sent from my iPad

? 2014-3-28?16:13?"ZL Huang" <admin@community.freescale.com<mailto:admin@community.freescale.com>> ???

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iMX6: how to trigger software reset

reply from ZL Huang<https://community.freescale.com/people/zlhuang?et=watches.email.thread> in i.MX Community - View the full discussion<https://community.freescale.com/message/391480?et=watches.email.thread#391480>

Re: iMX6: how to trigger software reset

zlhuang — Fri, 28 Mar 2014 10:51:26 GMT

I have tried to set WDOG2_WCR to 0xF3, but it does not work.

Could you suggest how to disable WDOG_B signal?

Thank you very much.

Re: iMX6: how to trigger software reset

AnsonHuang — Sun, 30 Mar 2014 09:39:13 GMT

If you want to not trigger WDOG_B signal, please write 0x4 to WCR to issue a wdog reset. If you want to trigger WDOG_B, using 0x14 instead.

You can try it.

The other option is just modify the IOMUX setting of WDOG_B MUX, set it to be other function.

Re: iMX6: how to trigger software reset

zlhuang — Tue, 01 Apr 2014 04:47:04 GMT

Dear Yongcai,

Our board config WDOG2 to be the output (MX6DL_PAD_GPIO_1__WDOG2_WDOG_B).

However, when I write 0x4 to WDOG1_WCR t to generate wdog_reset, I measured that the WDOG_B is also asserted.

I don't know if it is normal.

What should I do to disabe WDOG_B signal ( from WDOG2) before I generate WDOG1 wdog_reset?

BRs,

Re: iMX6: how to trigger software reset

AnsonHuang — Tue, 01 Apr 2014 05:00:44 GMT

This pin is also related to the board design, for example, when SOC is reset, this pin’s default state may also change, copy Gong Yibin.

Best Regards.

Anson Huang

Freescale Semiconductor Shanghai

Tel:021-28937058

Re: iMX6: how to trigger software reset

zlhuang — Tue, 01 Apr 2014 06:10:16 GMT

Dear Yongcai,

Do you mean we cannot disable the WDOG_B signal by software?

Thanks.

BRs,

Re: iMX6: how to trigger software reset

AnsonHuang — Tue, 01 Apr 2014 06:26:44 GMT

No, I meant you can disable WDOG_B pin function, such as set it to be other function, then trigger wdog reset by writting 0x4, then measure this pin to see whether it is asserted when wdog reset the system.

Re: iMX6: how to trigger software reset

zlhuang — Tue, 01 Apr 2014 06:35:19 GMT

Dear Yongcai,

Because I need the WDOG_B signal( from WDOG2), I cannot disable it.

I just want a simple wdog_reset function from WDOG1.

Thanks anyway.

BRs,

Re: iMX6: how to trigger software reset

AnsonHuang — Tue, 01 Apr 2014 06:37:22 GMT

I just want to identify the root cause, this is only to see whether it is related to board design, not final solution.