# Python Programming using MRAA (SPI)

1. Targeted Hardware    

SOM Version: PICM-001-A1

CB : RuggedBoard-A5D2X

CB Version : RB-A5D2X-V1.1

1. Targeted Software    

BSP-Yocto-A5D2X 2019-03-13

* AT91Bootstrap-3.8.12
* Linux Kernel v4.9.151
* uboot-2018-07
* Yocto 2.5.2 (sumo HEAD commit 623b77885051)

Description

* To test the SPI functionality in Kernel with loop-back test.

Required Hardware

* a5d2x-rugged board
* USB cable
* Patch cords

Step-by-step guide

* Boot the board from MMC. After booting connect the one end of patch card to MOSI pin and other end to MISO pin.
* Copy the spi.py python code in data directory of your board.
* Run the below python code.

Test spi.py

* Open spi.py program given below in your board terminal.
* Open the spi.py program in /data directory.

PROGRAM: spi.py

```
import mraa as m
import random as rand
import array

# intialise SPI
dev = m.Spi(0)

for x in range(0,100):
    txbuf = bytearray(4)
    for y in range(0,4):
        txbuf[y] = rand.randrange(0, 256)
 
# send and receive data through SPI
rxbuf = dev.write(txbuf)
if rxbuf != txbuf:
    print("Data mismatch!")
    exit(1)
print(rxbuf)
```

Execution :

Run the above code with below command in rugged board.

root\@ruggedboard-a5d2x:/data# python3 spi.py

Expected Output

When MISO & MOSI are short.

oot\@ruggedboard-a5d2x:/data# python3 spi.py\
libmraa\[149]: libmraa version v2.0.0 initialised by user 'root' with EUID 0\
libmraa\[149]: gpio: platform doesn't support chardev, falling back to sysfs\
libmraa\[149]: libmraa initialised for platform 'Atmel SAMA5' of type 20\
bytearray(b'\xd1\xa2\x80\x93')\
bytearray(b'z:l\x11')\
bytearray(b'WC\xf5\xd9')\
bytearray(b'\xcd\tq\xeb')\
bytearray(b'IEs\xfa')\
bytearray(b'\xbf\x1b\xe2b')\
bytearray(b'3l\x80\xe9')\
bytearray(b'\x8e\xf4\x05X')\
bytearray(b'C\n\xb0\xa5')\
bytearray(b'\x8f\xf5\xfe\xa1')\
bytearray(b'\xf8LPi')\
bytearray(b'"\xd5(z')\
bytearray(b'\x10\*F9')\
bytearray(b'\xaf\xbef\xe9')\
bytearray(b'\x80\xbd\x10C')\
bytearray(b'\xb6\x8e\xdc8')\
bytearray(b'k\xad\x96\xcc')\
bytearray(b'\xb8y\xael')\
bytearray(b'\xddwsT')\
bytearray(b'\x16\xfc\xcf\x9f')\
bytearray(b'\xddu\x0f\xf8')\
bytearray(b'\x05\xbd\x06\xc7')\
bytearray(b'yaW\x00')\
bytearray(b'\xe7b\xfe\xf5')\
bytearray(b'\xca0\xd0\xf6')\
bytearray(b'\xbf\xdbH\xc5')\
bytearray(b'Cb\xfau')\
bytearray(b'\xc7\`c\x9e')\
bytearray(b'L\\\xec8')\
bytearray(b'\x8a(\xc0\xad')\
bytearray(b'\xeb\x9fm\~')\
bytearray(b'now\xc4')\
bytearray(b'\xc7]\x9b\xc6')\
bytearray(b'\x1c5W\xe7')\
bytearray(b'\xa9\xd2\xce\xd1')\
bytearray(b'\x95"\xd66')\
bytearray(b'h|\xb9\xb4')\
bytearray(b'\xff&/\xf9')\
bytearray(b'\x8f\xee\xc0d')\
bytearray(b'S=\xb5\x8b')\
bytearray(b'.\x94\x91\x96')\
bytearray(b'\x9c\xb0\x1fd')\
bytearray(b'\x83(\x03+')\
bytearray(b'\xee\xfb\x18\xde')\
bytearray(b'\xfb\xf8\x01\xf4')\
bytearray(b'\[\x89\_\x87')\
bytearray(b'|\x98\x7f\x8c')\
bytearray(b'n32\xe7')\
bytearray(b'Y\xc7\x9b\xda')\
bytearray(b'\xc0A\xc5p')\
bytearray(b'\x0e\xf5\x1e\x0f')\
bytearray(b'qse1')\
bytearray(b'5\xf5\x07\x1a')\
bytearray(b'\xf3\xe9y?')\
bytearray(b'\xcf\xc5om')\
bytearray(b'\x8c\xe3\x8d\xb9')\
bytearray(b'M9\x88\xa9')\
bytearray(b'\xcc\x80\x02\x1f')\
bytearray(b'\xee\x05\x8a\x99')\
bytearray(b'P8\x1ah')\
bytearray(b'\x9cT\xcb\xd0')\
bytearray(b'\xfa\x9c\xa1T')\
bytearray(b'\x98\x85\xca\x0b')\
bytearray(b'{\x0fS$')\
bytearray(b'\x80\x15\x9a\x1e')\
bytearray(b'\xd6c\xe2Q')\
bytearray(b'.\xc0\x14\xbf')\
bytearray(b'\xafV^G')\
bytearray(b'\x9a\xfd\x0c\x84')\
bytearray(b'\x8b\n\x03\x8a')\
bytearray(b'z\x02\[\xf4')\
bytearray(b'\x11\xa5My')\
bytearray(b'r\<V\xa2')\
bytearray(b'E\xb4\x1a\xec')\
bytearray(b'\xbap\x9c\xc4')\
bytearray(b'\xf5\x9eU\x85')\
bytearray(b'\x91\x8b\x014')\
bytearray(b'o\xf86\xcf')\
bytearray(b'"a>\x9b')\
bytearray(b'\x1e\x95\x86\x00')\
bytearray(b'\x16+)\t')\
bytearray(b'\x1f\xf7(E')\
bytearray(b'c\xdd\x97\xf5')\
bytearray(b'\x89\xbc\xfe\xb6')\
bytearray(b'W\xd0\x07\x01')\
bytearray(b'\x94?\x04Q')\
bytearray(b'\xf1\xfa\xcc\x17')

When MISO & MOSI are not short.

uninitialized urandom read (24 bytes read)                                                                                                                   libmraa\[135]: libmraa version v2.0.0 initialised by user 'root' with EUID 0                                                                                                       libmraa\[135]: gpio: platform doesn't support chardev, falling back to sysfs                                                                        libmraa\[135]: libmraa initialised for platform 'Atmel SAMA5' of type 20                                                              random: python3: uninitialized urandom read (2500 bytes read)                                                                             Data mismatch!