SPI – Serial Peripheral Interface Bus Protocol

This class provides bus protocol of serial peripheral interface (SPI) .

Constructor

machine.SPI

class machine.SPI(port, mode, clk, [group])

Parameter:

• port - Integer type. Channel selection: [0,1].
• mode - SPI working mode.
  Clock polarity CPOL: The pin level of clock signal SCLK when SPI is idle (0: low level; 1: high level)
  0 : CPOL=0, CPHA=0
  1 : CPOL=0, CPHA=1
  2: CPOL=1, CPHA=0
  3: CPOL=1, CPHA=1
• clk - Clock frequency.
  EC600N/EC600S/EC800N/BG95M3/EC600M/EC800M/EG912N:
  0 : 812.5 kHz
  1 : 1.625 MHz
  2 : 3.25 MHz
  3 : 6.5 MHz
  4 : 13 MHz
  5 : 26 MHz
  6：52 MHz
  EC600U/EC200U/EG915U:
  0 : 781.25 kHz
  1 : 1.5625 MHz
  2 : 3.125 MHz
  3 : 5 MHz
  4 : 6.25 MHz
  5 : 10 MHz
  6 : 12.5 MHz
  7 : 20 MHz
  8 : 25 MHz
  9 : 33.33 MHz
  BC25：
  0 : 5 MHz
  X : X MHz (X in [1,39])
• [gruop] - map SPI to different pins,default value is 0.
  

BC25 series module does not support SPI working mode of value 1 or 2.

The group parameter is supported only by the EC600M/EC800M/EG810M series. nor flash cannot be mounted if group = 1

52MHz clk is high requirements for hardware.

Example:

>>> from machine import SPI
>>> # Creates a SPI object
>>> spi_obj = SPI(1, 0, 1)

SPI Pin Correspondences:

Methods

SPI.read

SPI.read(recv_data, datalen)

This method reads data.

Parameter:

• recv_data - Bytearray type. An array used to receive data.
• datalen - Integer type. Length of the data to be read.

Return Value:

0 - Successful execution

-1 - Failed execution

SPI.write

SPI.write(data, datalen)

This method writes data.

Parameter:

• data - Bytearray type. Data to be written.
• datalen - Integer type. Length of data to be written.

Return Value:

0 - Successful execution

-1 - Failed execution

SPI.write_read

SPI.write_read(r_data, data, datalen)

This method writes and reads data.

Parameter:

• r_data - Bytearray type. An array used to receive data.
• data - Bytearray type. Data to be sent.
• datalen - Integer type. Length of data to be read.

Return Value:

0 - Successful execution

-1 - Failed execution

SPI.close

SPI.close()

This method close SPI.

Return Value:

0 - Successful execution

-1 - Failed execution

Example:

Please use this function with the peripherals.

import log
from machine import SPI
import utime



spi_obj = SPI(0, 0, 1)

# Sets the log output level 
log.basicConfig(level=log.INFO)
spi_log = log.getLogger("SPI")


if __name__ == '__main__':
    r_data = bytearray(5)  # Creates a buff for receiving data
    data = b"world"  # Tests data

    ret = spi_obj.write_read(r_data, data, 5)  # Writes data and receives data to r_data
    spi_log.info(r_data)