Is it possible to freely use the RTC Fast Memory for data storage? I would like to use it to store data during deep sleep. But I am unclear if the default wakeup stub resides there.

Thanks.

ESP_Angus,

Thanks for the response. It was helpful. Sorry I didn't reply earlier. This set up the first phase correctly for me.

mos flash --esp-flash-params dio,32m,80m

I had trouble getting the flash size right. I thought 4m for 4 megabyte and it would error. 32m worked.

Paul

Adafruit Huzzah32
Mongoose-os

My sdkconfig file has this:

CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
CONFIG_ESPTOOLPY_FLASHFREQ_40M=
CONFIG_ESPTOOLPY_FLASHFREQ_26M=
CONFIG_ESPTOOLPY_FLASHFREQ_20M=
CONFIG_ESPTOOLPY_FLASHFREQ="80m"

But the second stage boot message is this:
[Sep 9 10:52:25.021] [0;32mI (29) boot: ESP-IDF v3.0-r11 2nd ...

When I execute this code

void deep_sleep_start(void){
ESP_ERROR_CHECK(esp_wifi_stop());
ESP_ERROR_CHECK(esp_bluedroid_disable());
ESP_ERROR_CHECK(esp_bluedroid_deinit());
ESP_ERROR_CHECK(esp_bt_controller_disable());
ESP_ERROR_CHECK(esp_bt_controller_deinit());
ESP_ERROR_CHECK(esp_sleep ...

My i2c read seems to block / stall my ULP code. I am using legacy macros, and needed to write the macro for the read and write instruction - which I posted to another thread. But not sure why it stalls. Also no indication of pin activity on SCL. Here is my register setup. Note: I tried using rtc ...

For what its worth here is the missing macros I defined. The i2c fields are defined in ulp.h. However when I run this opcode in the ulp it appears to stall and my ulp code does not wake up from deep sleep. I have tried setting things up the registers as per the technical reference.

Does anyone have ...

I'm programming the ulp processor using legacy macros. I looked at ulp.h. I don't see a macro defined for i2c_rd and i2c_wr. I assume it would be I_I2C_RD and I_I2C_WR. I see the opcode bit definitions in ulp_insn_t but no macros. Did I miss something?