Driver AT Commands
AT+DRVADC: Read ADC channel value.
AT+DRVPWMINIT: Initialize PWM driver.
AT+DRVPWMDUTY: Set PWM duty.
AT+DRVPWMFADE: Set PWM fade.
AT+DRVI2CINIT: Initialize I2C master driver.
AT+DRVI2CRD: Read I2C data.
AT+DRVI2CWRDATA: Write I2C data.
AT+DRVI2CWRBYTES: Write no more than 4 bytes I2C data.
AT+DRVSPICONFGPIO: Configure SPI GPIO.
AT+DRVSPIINIT: Initialize SPI master driver.
AT+DRVSPIRD: Read SPI data.
AT+DRVSPIWR: Write SPI data.
Introduction
Important
The default AT firmware does not support the AT commands listed on this page. If you need ESP32-C3 to support driver commands, you can compile the ESP-AT project by following the steps in Compile ESP-AT Project Locally documentation. In the project configuration during the fifth step, make the following selections:
Enable
Component config->AT->AT driver command support
AT+DRVADC: Read ADC Channel Value
Parameters
<channel>: ADC1 channel.
For ESP32-C3 devices, the range is [0,4].
CHANNEL
GPIO
0
GPIO0
1
GPIO1
2
GPIO2
3
GPIO3
4
GPIO4
<atten>: attenuation.
0: 0 dB attenuation, effective measurement range is [0, 750] mV.
1: 2.5 dB attenuation, effective measurement range is [0, 1050] mV.
2: 6 dB attenuation, effective measurement range is [0, 1300] mV.
3: 11 dB attenuation, effective measurement range is [0, 2500] mV.
<raw data>: ADC channel value.
Notes
ESP-AT only supports ADC1.
ESP32-C3 support 12-bit width.
For details on how to convert the channel value into voltage, please refer to ADC Conversion.
Example
// For ESP32-C3, 0 dB attenuation, effective measurement range is [0, 750] mV
// The returned 2048 means the voltage is 2048 / 4095 * 750 = 375.09 mV
AT+DRVADC=0,0
+DRVADC:2048
OK
AT+DRVPWMINIT: Initialize PWM Driver
Parameters
<freq>: LEDC timer frequency. Unit: Hz. Range: 1 Hz ~ 8 MHz.
<duty_res>: LEDC channel duty resolution. Range: 0 ~ 20 bits.
<chx_gpio>: LEDC output GPIO number of channel x. For example, if you want to use GPIO16 as channel 0, set <ch0_gpio> to 16.
Notes
AT can support a maximum of 4 channels.
The number of channels that you initialize using this command will determine how many channels you can set using other PWM commands, including AT+DRVPWMDUTY and AT+DRVPWMFADE. For example, if you initialize two channels, you can only change the two channels’ PWM duty using command
AT+DRVPWMDUTY.The frequency and the duty resolution are interdependent. See Supported Range of Frequency and Duty Resolutions for more details.
Example
AT+DRVPWMINIT=5000,13,17,16,18,19 // set 4 channels; frequency: 5 kHz; duty resolution: 13 bits
AT+DRVPWMINIT=10000,10,17 // only use channel 0, frequency: 10 kHz; duty resolution: 10 bits; other PMW commands can only set one channel
AT+DRVPWMDUTY: Set PWM Duty
Parameter
<duty>: LEDC channel duty. Range: [0,2 duty_resolution].
Notes
AT can support a maximum of 4 channels.
If you do not want to set
<duty>for a specific channel, just omit it.
Example
AT+DRVPWMDUTY=255,512 // set channel 0 to duty 255, set channel 1 to duty 512
AT+DRVPWMDUTY=,,0 // set channel 2 to duty 0
AT+DRVPWMFADE: Set PWM Fade
Set Command
Command:
AT+DRVPWMFADE=<ch0_target_duty>,<ch0_fade_time>[,...,<ch3_target_duty>,<ch3_fade_time>]
Response:
OK
Parameters
<target_duty>: target duty of fading. Range: [0, 2 duty_resolution–1].
<fade_time>: the maximum time of fading. Unit: millisecond.
Notes
AT can support a maximum of 4 channels.
If you do not want to set
<target_duty>and<fade_time>for a specific channel, just omit them.
Example
AT+DRVPWMFADE=,,0,1000 // use one second to change channel 1 duty to 0
AT+DRVPWMFADE=1024,1000,0,2000, // use one second time to change channel 0 duty to 1024, two seconds to change channel 1 duty to 0
AT+DRVI2CINIT: Initialize I2C Master Driver
Parameters
<num>: I2C port number. Range: 0 ~ 1. If the following parameters are not set, AT will deinitialize the I2C port.
<scl_io>: GPIO number for I2C SCL signal.
<sda_io>: GPIO number for I2C SDA signal.
<clock>: I2C clock frequency for master mode. Unit: Hz. Maximum: 1 MHz.
Note
This command only supports I2C masters.
Example
AT+DRVI2CINIT=0,25,26,1000 // initialize I2C0; GPIO25 is SCL; GPIO26 is SDA; I2C clock is 1 kHz
AT+DRVI2CINIT=0 // deinitialize I2C0
AT+DRVI2CRD: Read I2C Data
Parameters
<num>: I2C port number. Range: 0 ~ 1.
<address>: I2C slave device address.
7-bit address: 0 ~ 0x7F.
10-bit address: The first seven bits of the first byte are the combination 1111 0XX of which the last two bits (XX) are the two Most Significant Bits (MSBs) of the 10-bit address. For example, if the 10-bit address is 0x2FF (b’1011111111), the input address should be 0x7AFF (b’111101011111111).
<length>: I2C data length. Range: 1 ~ 2048.
<read data>: I2C data.
Note
I2C transmission timeout is one second.
Example
AT+DRVI2CRD=0,0x34,1 // I2C0 reads one byte data from address 0x34
AT+DRVI2CRD=0,0x7AFF,1 // I2C0 reads one byte data from 10-bit address 0x2FF
// I2C0 reads address 0x34, register address 0x27, read 2 bytes
AT+DRVI2CWRBYTES=0,0x34,1,0x27 // I2C0 first writes device address 0x34, register address 0x27
AT+DRVI2CRD=0,0x34,2 // I2C0 reads 2 bytes
AT+DRVI2CWRDATA: Write I2C Data
Set Command
Command:
AT+DRVI2CWRDATA=<num>,<address>,<length>
Response:
OK
>
This response indicates that you should enter the data you want to write. When the requirement of data length is met, the data transmission starts.
If the data is transmitted successfully, AT returns:
OK
If the data transmission fails, AT returns:
ERROR
Parameters
<num>: I2C port number. Range: 0 ~ 1.
<address>: I2C slave device address.
7-bit address: 0 ~ 0x7F.
10-bit address: The first seven bits of the first byte are the combination 1111 0XX of which the last two bits (XX) are the two Most Significant Bits (MSBs) of the 10-bit address. For example, if the 10-bit address is 0x2FF (b’1011111111), the input address should be 0x7AFF (b’111101011111111).
<length>: I2C data length. Range: 1 ~ 2048.
Note
I2C transmission timeout is one second.
Example
AT+DRVI2CWRDATA=0,0x34,10 // I2C0 writes 10 bytes data to address 0x34
AT+DRVI2CWRBYTES: Write No More Than 4 Bytes I2C Data
Parameters
<num>: I2C port number. Range: 0 ~ 1.
<address>: I2C slave device address.
7-bit address: 0 ~ 0x7F.
10-bit address: The first seven bits of the first byte are the combination 1111 0XX of which the last two bits (XX) are the two Most Significant Bits (MSBs) of the 10-bit address. For example, if the 10-bit address is 0x2FF (b’1011111111), the input address should be 0x7AFF (b’111101011111111).
<length>: the length of the I2C data you want to write. Range: 1 ~ 4 bytes.
<data>: the data of
<length>long. Range: 0 ~ 0xFFFFFFFF.
Note
I2C transmission timeout is one second.
Example
AT+DRVI2CWRBYTES=0,0x34,2,0x1234 // I2C0 writes 2 bytes data 0x1234 to address 0x34
AT+DRVI2CWRBYTES=0,0x7AFF,2,0x1234 // I2C0 writes 2 bytes data 0x1234 to 10-bit address 0x2FF
// I2C0 writes address 0x34; register address: 0x27; data: c0xFF
AT+DRVI2CWRBYTES=0,0x34,2,0x27FF
AT+DRVSPICONFGPIO: Configure SPI GPIO
Parameters
<mosi>: GPIO pin for Master Out Slave In signal.
<miso>: GPIO pin for Master In Slave Out signal, or -1 if not used.
<sclk>: GPIO pin for SPI Clock signal.
<cs>: GPIO pin for slave selection signal, or -1 if not used.
AT+DRVSPIINIT: Initialize SPI Master Driver
Set Command
Command:
AT+DRVSPIINIT=<clock>,<mode>,<cmd_bit>,<addr_bit>,<dma_chan>[,bits_msb]
Response:
OK
Parameters
<clock>: Clock speed, divisors of 80 MHz. Unit: Hz. Maximum: 40 MHz.
<mode>: SPI mode. Range: 0 ~ 3.
<cmd_bit>: Default amount of bits in command phase. Range: 0 ~ 16.
<addr_bit>: Default amount of bits in address phase. Range: 0 ~ 64.
<dma_chan>: Either channel 1 or 2, or 0 in the case when no DMA is required.
<bits_msb>: SPI data format:
Bit0:
0: Transmit MSB first (default).
1: Transmit LSB first.
Bit1:
0: Receive data MSB first (default).
1: Receive data LSB first.
Note
You should configure SPI GPIO before SPI initialization.
Example
AT+DRVSPIINIT=102400,0,0,0,0,3 // SPI clock: 100 kHz; mode: 0; both command and address bits are 0; not use DMA; transmit and receive LSB first
OK
AT+DRVSPIINIT=0 // delete SPI Driver
OK
AT+DRVSPIRD: Read SPI Data
Set Command
Command:
AT+DRVSPIRD=<data_len>[,<cmd>,<cmd_len>][,<addr>,<addr_len>]
Response:
+DRVSPIRD:<read data>
OK
Parameters
<data_len>: length of SPI data you want to read. Range: 1 ~ 4092 bytes.
<cmd>: command data. The length of the data is set in
<cmd_len>.<cmd_len>: command length in this transaction. Range: 0 ~ 2 bytes.
<addr>: command address. The length of the address is set in
<addr_len>.<addr_len>: The address length in this transaction. Range: 0 ~ 4 bytes.
Note
If you do not use DMA, the maximum
<data_len>you can set is 64 bytes each time.
Example
AT+DRVSPIRD=2 // read 2 bytes data
+DRVI2CREAD:ffff
OK
AT+DRVSPIRD=2,0x03,1,0x001000,3 // read 2 bytes data; <cmd> is 0x03; <cmd_len> is 1 byte; <addr> is 0x1000; <addr_len> is 3 bytes
+DRVI2CREAD:ffff
OK
AT+DRVSPIWR: Write SPI Data
Set Command
Command:
AT+DRVSPIWR=<data_len>[,<cmd>,<cmd_len>][,<addr>,<addr_len>]
Response:
When <data_len> is larger than 0, AT returns:
OK
>
This response indicates that you should enter the data you want to write. When the requirement of data length is met, the data transmission starts.
If the data is transmitted successfully, AT returns:
OK
When <data_len> is equal to 0, which means AT transmits commands and addresses only, and no SPI data, AT returns:
OK
Parameters
<data_len>: SPI data length. Range: 0 ~ 4092.
<cmd>: command data. The length of the data is set in
<cmd_len>.<cmd_len>: command length in this transaction. Range: 0 ~ 2 bytes.
<addr>: command address. The length of the address is set in
<addr_len>.<addr_len>: The address length in this transaction. Range: 0 ~ 4 bytes.
Note
If you do not use DMA, the maximum
<data_len>you can set is 64 bytes each time.
Example
AT+DRVSPIWR=2 // write 2 bytes data
OK
> // begin receiving serial data
OK
AT+DRVSPIWR=0,0x03,1,0x001000,3 // write 0 byte data; <cmd> is 0x03; <cmd_len> is 1 byte; <addr> is 0x1000; <addr_len> is 3 bytes
OK