Disabling boot log (MTDO pin) on ESP-WROOM-32

[davdav]

Hi everybody,

I would like to eliminate the early boot log, such as

Code: Select all

ets Jun  8 2016 00:22:57

rst:0x10 (RTCWDT_RTC_RESET),boot:0x1b (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:4068
load:0x40078000,len:0
load:0x40078000,len:14220
entry 0x4007857c

I know this can be avoid pulling down MTDO (i.e. GPIO15) pin. Unfortunately I'm using that pin for 1-line SD-card and GPIO15 is used as SD_CMD which is pullup-up by an external 10Kohm resistor.


Is there a way to use espefuse.py to disable the boot log without rely on GPIO15 status?


Thanks

[loboris]

To disable the ROM log, GPIO15 has to be pulled low only during the very short period when the power is applied to the ESP32 (Power on reset).
After that it can be used normaly for SD card interface. On all other kinds of resets GPIO15 can remain high and no ROM log will be emited.
A simple circuit can be designed wich holds GPIO15 low for couple of ms when power is connected.

[davdav]

Thanks @Loboris,

boot ROM log is also sent out in case of esp_restart() is perfomed. You will get:

Code: Select all

ets Jun  8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x1b (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:4068
load:0x40078000,len:0
load:0x40078000,len:14220
entry 0x4007857c

so I guess your proposed circuit will not work. By the way our PCB is already done and we can't add other components (cost reason).

I'm looking for a solution described here for GPIO12
https://github.com/espressif/esp-idf/tr ... out-gpio12

Is it possible to ask for pull request to add a similar feature for GPIO15?

Thanks.

[WiFive]

No there is no efuse for that function

[loboris]

boot ROM log is also sent out in case of esp_restart() is perfomed

I don't get any boot ROM log after executing esp_restart() if the GPIO15 was pulled low on power on and then released.
SDCard was used before reset.

Hard reset (pulling EN low) has the same effect as power on, GPIO15 must be low for no boot ROM log.

[davdav]

Ok @Loboris.understood.Gpio15 must be low at the very first power on to disabile log..

As stated by @wifive there is no efuse to use.

Is it possible to modify any source code on bootloader to avoid this? Is the first stage bootloader "hackable"?

Thanks

[WiFive]

No it is mask ROM.