#! /usr/bin/env python

import ftdi

idVendor = 0x0403
idProduct = 0x6011
# Clock X5 Command for H class component
TCK_X5 = 0x8a
CLK_MAX_SPEED5X = 30000000
SPI_MAX_MSG_SIZE = 64*1024 # 65536


def send_buf(ftdic, buf, size):
    if (ftdi.ftdi_write_data(ftdic, buf, size) < 0):
        print "ftdi_write_data < 0", ftdi.ftdi_get_error_string(ftdic)
        return True
    else:
        print "ftdi_write_data worked..."
        return False

def get_buf(ftdic, buf, size):
    if (ftdi.ftdi_read_data(ftdic, buf, size) < 0):
        print "ftdi_read_data < 0", ftdi.ftdi_get_error_string(ftdic)
        return True
    else:
        print "ftdi_read_data worked..."
        return False


def spi_init(ftdic):
    if (ftdi.ftdi_init(ftdic) < 0):
        print "ftdi_init failed"
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_usb_open(ftdic, idVendor, idProduct) < 0):
        print "Unable to open ftdi device:", ftdi.ftdi_get_error_string(ftdic)
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_write_data_set_chunksize(ftdic, 512)):
        print "Unable to set chunk size (512)"
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_set_interface(ftdic, ftdi.INTERFACE_D) < 0):
        print "Unable to select interface D:", ftdi.INTERFACE_D
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_set_interface(ftdic, ftdi.INTERFACE_C) < 0):
        print "Unable to select interface D:", ftdi.INTERFACE_C
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_set_interface(ftdic, ftdi.INTERFACE_B) < 0):
        print "Unable to select interface D:", ftdi.INTERFACE_B
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_set_interface(ftdic, ftdi.INTERFACE_A) < 0):
        print "Unable to select interface A:", ftdi.INTERFACE_A
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_usb_reset(ftdic) < 0):
        print "Unable to reset FTDI device"
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_set_latency_timer(ftdic, 2) < 0):
        print "Unable to set latency timer"
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_set_bitmode(ftdic, 0x00, ftdi.BITMODE_MPSSE) < 0):
        print "Unable to set bitmode to SPI"
        close(ftdic)
        exit(-1)

    if (ftdi.ftdi_usb_purge_buffers(ftdic) < 0):
        print "Unable to purge usb buffers"
        close(ftdic)
        exit(-1)

def set_clock(ftdic, speed):
    print "Disable divide-by-5 front stage"
    if send_buf(ftdic, chr(TCK_X5), 1):
        print "divide-by-5"
        close(ftdic)
        exit(-1)

    print "Set clock divisor...."
    div = (CLK_MAX_SPEED5X / speed) - 1
    print 'div:',div
    buf0 = chr(ftdi.TCK_DIVISOR) # command "set divisor"
    buf1 = chr(div & 0xFF)
    buf2 = chr(((div >> 8) & 0xFF))
    buf = buf0 + buf1 + buf2
    if send_buf(ftdic, buf, 3):
        print "clock divisor"
        close(ftdic)
        exit(-1)

    print "YESS!!!"


def set_loopback(ftdic, active):
    if active:
        if send_buf(ftdic, chr(ftdi.LOOPBACK_START), 1):
            print "loopback activate"
            close(ftdic)
            exit(-1)
    else:
        if send_buf(ftdic, chr(ftdi.LOOPBACK_END), 1):
            print "loopback de-activate"
            close(ftdic)
            exit(-1)

def write(ftdic, message):
    # No type checking but assume client calls function properly
    size = len(message)
    send_buf(ftdic, message, size)

def close(ftdic):
    ftdi.ftdi_usb_close(ftdic)
    ftdi.ftdi_deinit(ftdic)


# Main
if __name__ == "__main__":
    ftdic = ftdi.ftdi_context()
    spi_init(ftdic)
    set_clock(ftdic, CLK_MAX_SPEED5X)
    set_loopback(ftdic, False)
    write(ftdic, "Test")
    close(ftdic)