A quick and dirty Python script to test Raspberry Pi SPI communication with a Microchip 23LCV512 SRAM (512kbit). See comments for requirements.

rpi-test-sram.py

#!/usr/bin/python2
#
# requires SPI kernel module (sudo modprobe spi_bcm2708)
# requires spi.so from https://github.com/lthiery/SPI-Py
# 

from __future__ import print_function
import spi
import os
from random import randint
import time

print('setting up spi...', end='')
status = spi.openSPI(speed=20000000)
print('%s' % status)

#read sram mode register
mode = spi.transfer((0x05,0))[1]
if mode == 0: modeType = "byte"
elif mode == 64: modeType = "sequential"
elif mode == 128: modeType = "page"
else: modeType = "unknown"
print('read mode register: %s (%s)\n' % ('{0:08b}'.format(mode), modeType))

#set some static variables
WRITE = 0x02
READ = 0x03
DATA = (0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xAD, 0xF0, 0x0D) * 256
SIZE = len(DATA)
LAST_ADDR = float(0xFFFF)
BLOCKS = int(round(LAST_ADDR/SIZE))

#fill the SRAM with data 2Kb at a time
print('filling 512kbit of memory with %s*%s bit blocks...' % (BLOCKS, SIZE))
start = time.time()
print('#\tlocation')
for write in range(0,(BLOCKS)):
    loc = ((write*SIZE))
    print('%s\t0x%04x' % (write ,loc))
    x,y = divmod(loc, 0x100)
    spi.transfer((WRITE, x, y) + DATA)
    #uncomment to error check each block after write
    #if DATA != (spi.transfer((READ, x, y) + (0,) * SIZE)[3:]): print('error')
end = time.time()
#time isn't 100% accurate, but good enough to get an idea
print('\ndone in %s seconds\n' % (end-start))

#now do some random error checking to make sure we read back the right data
for x in range(0,5):
    mem = (randint(0,BLOCKS)*SIZE)
    print('reading random %s byte memory segment 0x%04x: ' % (SIZE, mem), end='')
    x,y = divmod(mem, 0x100)
    #first three bytes returned are null as we're instructing the SRAM
    #to read, loc byte 1, loc byte 2, then it spits out data
    randomMem = (spi.transfer((READ, x, y) + (0,) * SIZE)[3:])
    if DATA != randomMem: print('error!')
    else: print('data matches!')

print('\nfin')

Hi, I need to communicate raspberry pi 3 and SRAM "MX25L6436E" which is present in other card through spi communication.
what are the changes i need to do in this script to use it.
i am quite new to python, please tell me script changes or any other changes as well if needed.