def test_gpio_loopback(self):
"""Check I/O.
"""
if self.skip_loopback:
raise SkipTest('Skip loopback test on multiport device')
gpio = GpioAsyncController()
direction = 0xFF & ~((1 << 4) - 1) # 4 Out, 4 In
gpio.configure(self.url, direction=direction, frequency=800000)
for out in range(16):
# print(f'Write {out:04b} -> {out << 4:08b}')
gpio.write(out << 4)
fback = gpio.read()
lsbs = fback & ~direction
msbs = fback >> 4
# check inputs match outputs
self.assertEqual(lsbs, out)
# check level of outputs match the ones written
self.assertEqual(msbs, out)
outs = list([(out & 0xf) << 4 for out in range(1000)])
gpio.write(outs)
gpio.ftdi.read_data(512)
for _ in range(len(outs)):
_ = gpio.read(14)
last = outs[-1] >> 4
for _ in range(10):
fbacks = gpio.read(1000)
for fback in fbacks:
lsbs = fback & ~direction
msbs = fback >> 4
# check inputs match last output
self.assertEqual(lsbs, last)
# check level of output match the last written
self.assertEqual(msbs, last)
gpio.close()
def transmitAsync(self, halfPeriod=0.005):
gpio = GpioAsyncController()
gpio.configure(self.device, self.directionArray[0])
for i in range(len(self.txArray)):
if (self.directionArray[i] != self.directionArray[i-1]):
time.sleep(halfPeriod)
gpio.close()
gpio = GpioAsyncController()
gpio.configure(self.device, self.directionArray[i])
time.sleep(halfPeriod)
#print("new direction: "+hex(self.directionArray[i]))
# read the state of the port
self.rxArray.append( gpio.read() )
#print("read: "+hex(self.rxArray[-1]))
# write to the outputs (0 is OK to write to inputs)
gpio.write(self.txArray[i])
#print("write: "+hex(self.txArray[i]))
# wait half a clock cycle
time.sleep(halfPeriod)
gpio.close()
def test_gpio_baudate(self):
# this test requires an external device (logic analyser or scope) to
# check the bitbang read and bitbang write signal (BB_RD, BB_WR) and
# mesure their frequency. The EEPROM should be configured to enable
# those signal on some of the CBUS pins, for example.
gpio = GpioAsyncController()
direction = 0xFF & ~((1 << 4) - 1) # 4 Out, 4 In
gpio.configure(self.url, direction=direction)
buf = bytes([0xf0, 0x00, 0xf0, 0x00, 0xf0, 0x00, 0xf0, 0x00])
freqs = [50e3, 200e3, 1e6, 3e6]
if gpio.ftdi.is_H_series:
freqs.extend([6e6, 10e6, 12e6])
gpio.read(128)
for freq in freqs:
# set the bitbang refresh rate
gpio.set_frequency(freq)
self.assertEqual(gpio.frequency, freq)
# be sure to leave enough time to purge buffers (HW FIFO) or
# the frequency changes occur on the current buffer...
gpio.write(buf)
gpio.read(128)
sleep(0.01)
gpio.close()
class FtdiDevice:
"""FTDI FT2232H SPI master to access FPGA Control/Status Registers (CSR)
plus some GPIO control.
SPI parameters:
- FTDI channel B:
* BDBUS0 - SCLK
* BDBUS1 - MOSI
* BDBUS2 - MISO
* BDBUS3 - CSn
- slave;
- mode 0 only;
- most significant bit transmitted first;
- byte order from high to low;
- SCK frequency must at least 8 lower than system frequency.
There are 2 types of SPI transactions:
- incremental burst -- address increments internally after every data (array)
- fixed burst -- one adreess, multiple data (FIFO)
Transaction is done with 8-bit address and 16 bit data words.
Transaction format:
- control word (3 bytes):
* bit 23 -- write (1) or read (0)
* bit 22 -- burst incremental (1) or fixed (0)
* bit 21 .. 8 -- 14 bit length (0 - 1 data word, 1 - 2 data words, etc)
* bits 7 .. 0 -- 8 bit address
- data word (2 bytes) 1 .. N:
* bits 15 .. 0 -- data to be written or readen
GPIO parameters:
- ADBUS7 - output - active low reset for FPGA configuration (ICE_RESET)
- BDBUS7 - output - active high reset for FPGA logic (ICE_RESET_FT)
"""
GPIO_RESET_LOGIC_POS = 7
GPIO_RESET_CONFIG_POS = 7
def __init__(self, ftdi_url, spi_freq=1E6):
"""Configure the FTDI interface.
Keyword arguments:
ftdi_url -- device url, which can be obtained by Ftdi.show_devices()
freq -- SPI frequency up to 8E6 (for FPGA running on 64 MHz)
"""
# Configure SPI master
self._spi_ctrl = SpiController()
self._spi_ctrl.configure(ftdi_url + '2') # second port - channel B
self._spi_port = self._spi_ctrl.get_port(cs=0, freq=spi_freq, mode=0)
# Configure FPGA logic reset (ICE_RESET_FT)
self._spi_gpio = self._spi_ctrl.get_gpio()
self._spi_gpio.set_direction(1 << self.GPIO_RESET_LOGIC_POS,
1 << self.GPIO_RESET_LOGIC_POS)
self._spi_gpio.write(0)
# Configure FPGA configuration reset (ICE_RESET)
self._gpio_ctrl = GpioAsyncController()
self._gpio_ctrl.configure(
ftdi_url + '1', # first port - channel A
direction=(1 << self.GPIO_RESET_CONFIG_POS),
frequency=1e6,
initial=(1 << self.GPIO_RESET_CONFIG_POS))
self._gpio_ctrl.write(1 << self.GPIO_RESET_CONFIG_POS)
def _int_to_bytes(self, i, length=2):
"""Convert integer to bytes"""
return int.to_bytes(i, length=length, byteorder='big', signed=False)
def _words_to_bytes(self, words_list):
"""Convert list with 16 bit words to bytes"""
bytes_str_list = [self._int_to_bytes(w, length=2) for w in words_list]
return b''.join(bytes_str_list) # concatenate all strings
def _bytes_to_words(self, bytes_str):
"""Convert bytes string to list with 16 bit words"""
return [
int.from_bytes(bytes_str[b * 2:b * 2 + 2],
byteorder='big',
signed=False) for b in range(len(bytes_str) // 2)
]
def _prepare_ctrl_word(self, addr, len, burst, wr):
"""Prepare control word for exchange.
Keyword arguments:
addr -- 8 bit address
len -- number of 16 bit data words to write/read (2^14 max)
burst -- 'fixed' address the same for every data, 'incr' - address + 1 for every next data word
wr -- 1 for write operation, 0 - for read
"""
ctrl_word = 0
ctrl_word |= (wr << 23)
ctrl_word |= ((burst == 'incr') << 22)
ctrl_word |= (((len - 1) & 0x3FFF) << 8)
ctrl_word |= ((addr & 0xFF) << 0)
return ctrl_word
def spi_read(self, addr, len=1, burst='fixed'):
"""Read data from address via SPI.
Keyword arguments:
addr -- 8 bit address
len -- number of 16 bit data words to write/read (2^14 max)
burst -- 'fixed' address the same for every data, 'incr' - address + 1 for every next data word
Return:
list of size 'len' with 16 bit data words
"""
ctrl_word = self._prepare_ctrl_word(addr, len, burst, wr=0)
rbytes = self._spi_port.exchange(self._int_to_bytes(ctrl_word, 3),
len * 2)
return self._bytes_to_words(rbytes)
def spi_write(self, addr, data, burst='fixed'):
"""Write data to address via SPI.
Keyword arguments:
addr -- 8 bit address
data -- list with 16 bit data words to write (list length 2^14 max)
burst -- 'fixed' address the same for every data, 'incr' - address + 1 for every next data word
"""
ctrl_word = self._prepare_ctrl_word(addr, len(data), burst, wr=1)
wbytes = self._int_to_bytes(ctrl_word, 3) + self._words_to_bytes(data)
self._spi_port.exchange(wbytes)
def reset_logic_on(self):
"""Activate reset pin ICE_RESET_FT"""
self._spi_gpio.write((1 << self.GPIO_RESET_LOGIC_POS)
| self._spi_gpio.read())
def reset_logic_off(self):
"""Deactivate reset pin ICE_RESET_FT"""
self._spi_gpio.write(~(1 << self.GPIO_RESET_LOGIC_POS)
& self._spi_gpio.read())
def reset_config_on(self):
"""Activate reset pin ICE_RESET"""
self._gpio_ctrl.write(~(1 << self.GPIO_RESET_CONFIG_POS)
& self._gpio_ctrl.read())
def reset_config_off(self):
"""Deactivate reset pin ICE_RESET"""
self._gpio_ctrl.write((1 << self.GPIO_RESET_LOGIC_POS)
| self._gpio_ctrl.read())
def close_connection(self):
"""Close FTDI interface"""
self._spi_ctrl.terminate()
self._gpio_ctrl.close()
