Start Bootloader From App

RE: Start Bootloader From App

ting² — Fri, 10 Jul 2015 12:46:29 GMT

When I have a look in main of the dfu. I need to set "app_reset" to true in order to enter in the bootloader. If "sd_power_gpregret_set(ENTER_BOOTLOADER_VALUE);" is not 0xB1. I will not have true for app_reset .

 bool     app_reset= (NRF_POWER->GPREGRET == BOOTLOADER_DFU_START); 
if (app_reset)
{
    NRF_POWER->GPREGRET = 0;
}	
  
dfu_start  = app_reset;
if (dfu_start || (!bootloader_app_is_valid(DFU_BANK_0_REGION_START)))
{
    err_code = bootloader_dfu_start();
    APP_ERROR_CHECK(err_code);

}

RE: Start Bootloader From App

John — Tue, 26 May 2015 11:43:48 GMT

@kerem is correct. The value is arbitrary. I chose 0xA5 but it can be any non zero value.

RE: Start Bootloader From App

kerem — Mon, 25 May 2015 14:11:46 GMT

Since you define it as a macro prior to using it on the application side, I don't think the value matters at all unless it's invalid in terms of macro definition.

RE: Start Bootloader From App

ting² — Mon, 25 May 2015 14:06:06 GMT

Hi, Which value did you used for ENTER_BOOTLOADER_VALUE? Is it the same value as BOOTLOADER_DFU_START(0xB1)?

RE: Start Bootloader From App

John — Mon, 04 May 2015 14:25:35 GMT

That control snippet is part of my on_write event handler for my proprietary service and characteristic. The p_received_command points to the data portion of the event which contains my proprietary commands including a enter bootloader command. It is declared like this:

	ble_gatts_evt_write_t	* p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
onset_recv_command_t	* p_received_command = (onset_recv_command_t *)&p_evt_write->data[0];

RE: Start Bootloader From App

kerem — Sat, 02 May 2015 22:41:19 GMT

I can see that once the received command is ENTER_RADIO_BOOTLOADER, your snipper clears the GPREGRET register and writes ENTER_BOOTLOADER_VALUE on it, so that your bootloader who is checking the register's value can go in DFU mode, that's fine. But I could not understand where does that whole control snippet go in your application? How p_received_command is actually populated? Is there an example I can refer to in the SDK that does something similar?

RE: Start Bootloader From App

michaeld — Fri, 17 Apr 2015 07:45:28 GMT

Smart! Thanks :)

RE: Start Bootloader From App

Scott Buchanan — Tue, 24 Jun 2014 22:41:23 GMT

Thanks so much, that works great!!! I understand your comments about pstorage, at which I'm less of an expert, but I would like to understand that better but haven't found any guide type documentation.

Seems to me there should be some way of writing a value to a memory location :) I know where the BOOT_SETTINGS are (0x3fc00) and their structure but, for now, your solution works great!!!

RE: Start Bootloader From App

John — Tue, 24 Jun 2014 21:14:19 GMT

I'll say up front that I am not a pstorage expert. That said, I believe that the bootloader application will allocate a pstorage area at the very top of memory. The bootloader is allocated the space right below its pstorage area. Then your application will create its own pstorage area beneath the bootloader. So it may be difficult for you to corrupt the bootloaders pstorage from the application FW.

I have a bit simpler mechanism for entering the bootloader in my application. When I receive the go into bootloader command from my host application, I set a value in the general purpose RAM retention register (GPREGRET) and reset. The bootloader init code looks at the GPREGRET and if my enter bootloader value is present, the bootloader is invoked. I'll put a code snippet from my applicaton below. Note, the reset is not performed in the command handler the command handler sets a flag that is checked elsewhere.

	if (p_received_command->parameters[0] == ENTER_RADIO_BOOTLOADER)
	{
		calc_response_length(O_CMD_SUCCESS);
		p_onset->cmd_resp_ready = true;
		
		set_enter_bootloader(true);
		
		err_code = sd_power_gpregret_clr(0xFF);
		if (err_code != NRF_SUCCESS)
		{
			ASSERT(false);
		}
		
		err_code = sd_power_gpregret_set(ENTER_BOOTLOADER_VALUE);
		if (err_code != NRF_SUCCESS)
		{
			ASSERT(false);
		}
		
		return;
	}