Writing over SPI to TCL LEDs from python

rainbow.py

#!/usr/bin/env python

import time
import math

def main():
    #fout = open('spidev','w')
    fout = open('/dev/spidev2.0', 'w')
    ctr = 0

    while True:
        outdata = []
        outdata.append('\x00\x00\x00\x00')
        for j in range(1250):
            h = 360.0/1250.0*((j+ctr)%1250)
            pval = hsv_to_rgb(h, 1.0, 1.0)
            t = [int(math.floor(255.0*p)) for p in pval]
            flag = (t[0]&0xc0)>>6
            flag |= (t[1]&0xc0)>>4
            flag |= (t[2]&0xc0)>>2
            flag ^= 0xff
            outdata.append('%c'%flag)
            outdata.append('%c'%t[2])
            outdata.append('%c'%t[1])
            outdata.append('%c'%t[0])

        outdata.append('\x00\x00\x00\x00')        
        outdata.append('\x00\x00\x00\x00')        

        fout.write(''.join(outdata))
        fout.flush()
        #sys.stdout.write(''.join(outdata))
        #sys.stdout.flush()
        time.sleep(0.02)
        ctr+=1

    fout.close()

def hsv_to_rgb(h, s, v):
    if s < 1.0e-6:
        return (v, v, v)

    h = h/60.0
    i = int(math.floor(h))
    f = h - i
    p = v*(1.0-s)
    q = v*(1.0-s*f)
    t = v*(1.0-s*(1.0-f))

    if i==0:
        return (v,t,p)
    elif i==1:
        return (q,v,p)
    elif i==2:
        return (p,v,t)
    elif i==3:
        return (p,q,v)
    elif i==4:
        return (t,p,v)
    else:
        return (v,p,q)

    return (0,0,0)

if __name__=='__main__':
    main()