Espressif Systems ESP8266EX - 2.3. Layout Design

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3. Sample Codes

3.2.8. Get RSSI (Received Signal Strength Indicator) of AP

1. If ESP8266 functions as Station and is not connected to an AP, users can obtain the

RSSI (Received Signal Strength Indicator) of an AP by scanning the AP with a speciﬁed

SSID.

Specify the SSID of the target AP:

#define󰲧DEMO_AP_SSID󰲧󰲧󰲧󰲧󰲧“DEMO_AP"

Scan the AP with a speciﬁed SSID. After the scanning is completed, scan_done will be

called back.

󰲧󰲧󰲧󰲧struct󰲧scan_config󰲧config;

󰲧󰲧󰲧󰲧memset(&config,󰲧0,󰲧sizeof(config));

󰲧󰲧󰲧󰲧config.ssid󰲧=󰲧DEMO_AP_SSID;

󰲧󰲧󰲧󰲧Wi-Fi_station_scan(&config,scan_done);

2. Compile the application program, generate ﬁrmware and download it into the ESP8266

module.

3. Power off the module, and change it to operation mode; then power on the module and

run the program.

Result:

Hello,󰲧welcome󰲧to󰲧scan-task!

scandone

(3,"DEMO_AP",-49,"aa:5b:78:30:46:0a",11)

3.2.9. Read and Write of Flash Memory

1. Read data from a ﬂash memory. It is essential that the data address be four-byte

aligned. Below is an example of how to read information from a ﬂash.

󰲧󰲧󰲧󰲧#define󰲧SPI_FLASH_SEC_SIZE󰲧󰲧󰲧󰲧󰲧󰲧󰲧󰲧4096

󰲧󰲧󰲧󰲧uint32󰲧value;

󰲧󰲧󰲧󰲧uint8󰲧*addr󰲧=󰲧(uint8󰲧*)&value;

󰲧󰲧󰲧󰲧spi_flash_read(0x3E󰲧*󰲧SPI_FLASH_SEC_SIZE,󰲧(uint32󰲧*)addr,󰲧4);

󰲧󰲧󰲧󰲧printf("0x3E󰲧sec:%02x%02x%02x%02x\r\n",󰲧addr[0],󰲧addr[1],󰲧addr[2],󰲧addr[3]);

2. Similarly, when writing data into sectors on a ﬂash memory, the data address should also

be four-byte aligned. Use spi_flash_erase_sector to erase the sector ﬁrst, then call

spi_flash_write to write data into it. For example,

󰲧󰲧󰲧󰲧uint32󰲧data[M];

󰲧󰲧󰲧󰲧//󰲧TODO:󰲧fit󰲧in󰲧the󰲧data

󰲧󰲧󰲧󰲧spi_flash_erase_sector(N);

󰲧󰲧󰲧󰲧spi_flash_write(N*4*1024,󰲧data,󰲧M*4);󰲧󰲧

Espressif

! /!13 37

2017.05

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