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Fixed size when polling length of FRAM to reflect actual size #7

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Merged
merged 9 commits into from
Jan 26, 2019
Merged

Fixed size when polling length of FRAM to reflect actual size #7

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7b483a6
Fixed length to show sizze rather than highest index
Jan 25, 2019
6eaae80
Changed max_size to actual max size. Updated all messages and examples.
Jan 25, 2019
238bfe3
Changed max_size to actual max size. Updated all messages and examples.
Jan 25, 2019
9b9e2f0
Fixed Travis Error
Jan 25, 2019
2c06cbc
Added suggestions by @danh. Fixed off by one error on slicing.
Jan 25, 2019
3aa23f3
Fixed Travis Errors
Jan 25, 2019
cae01f6
Changed many uses of register to address
Jan 25, 2019
f54ae85
Fixed Travis Error
Jan 25, 2019
5365bea
Fixed Zero Address Check
Jan 25, 2019
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70 changes: 35 additions & 35 deletions adafruit_fram.py
100644 → 100755
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Original file line number Diff line number Diff line change
Expand Up @@ -51,8 +51,8 @@
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_FRAM.git"

_MAX_SIZE_I2C = const(32767)
_MAX_SIZE_SPI = const(8191)
_MAX_SIZE_I2C = const(32768)
_MAX_SIZE_SPI = const(8192)

_I2C_MANF_ID = const(0x0A)
_I2C_PROD_ID = const(0x510)
Expand Down Expand Up @@ -80,7 +80,7 @@ def __init__(self, max_size, write_protect=False, wp_pin=None):
@property
def write_wraparound(self):
""" Determines if sequential writes will wrapaound highest memory address
(``len(FRAM)``) address. If ``False``, and a requested write will
(``len(FRAM) - 1``) address. If ``False``, and a requested write will
extend beyond the maximum size, an exception is raised.
"""
return self._wraparound
Expand All @@ -106,14 +106,14 @@ def write_protected(self):
return self._wp if self._wp_pin is None else self._wp_pin.value

def __len__(self):
""" The maximum size of the current FRAM chip. This is the highest
""" The size of the current FRAM chip. This is one more than the highest
register location that can be read or written to.

.. code-block:: python

fram = adafruit_fram.FRAM_xxx() # xxx = 'I2C' or 'SPI'

# maximum size returned by len()
# size returned by len()
len(fram)

# can be used with range
Expand All @@ -122,7 +122,7 @@ def __len__(self):
return self._max_size


def __getitem__(self, key):
def __getitem__(self, address):
""" Read the value at the given index, or values in a slice.

.. code-block:: python
Expand All @@ -133,28 +133,29 @@ def __getitem__(self, key):
# read values 0 thru 9 with a slice
fram[0:9]
"""
if isinstance(key, int):
if key > self._max_size:
raise ValueError("Register '{0}' greater than maximum FRAM size."
" ({1})".format(key, self._max_size))
if isinstance(address, int):
if not 0 < address < self._max_size:
raise ValueError("Address '{0}' out of range. It must be 0 <= address < {1}."
.format(address, self._max_size))
buffer = bytearray(1)
read_buffer = self._read_register(key, buffer)
elif isinstance(key, slice):
if key.step is not None:
read_buffer = self._read_register(address, buffer)
elif isinstance(address, slice):
if address.step is not None:
raise ValueError("Slice stepping is not currently available.")

registers = list(range(key.start if key.start is not None else 0,
key.stop if key.stop is not None else self._max_size))
if (registers[0] + len(registers)) > self._max_size:
raise ValueError("Register + Length greater than maximum FRAM size."
" ({0})".format(self._max_size))
regs = list(range(address.start if address.start is not None else 0,
address.stop + 1 if address.stop is not None else self._max_size))
if regs[0] < 0 or (regs[0] + len(regs)) > self._max_size:
raise ValueError("Address slice out of range. It must be 0 <= [starting address"
":stopping address] < {0}."
.format(self._max_size))

buffer = bytearray(len(registers))
read_buffer = self._read_register(registers[0], buffer)
buffer = bytearray(len(regs))
read_buffer = self._read_register(regs[0], buffer)

return read_buffer

def __setitem__(self, key, value):
def __setitem__(self, address, value):
""" Write the value at the given starting index.

.. code-block:: python
Expand All @@ -168,18 +169,17 @@ def __setitem__(self, key, value):
if self.write_protected:
raise RuntimeError("FRAM currently write protected.")

if isinstance(key, int):
if isinstance(address, int):
if not isinstance(value, (int, bytearray, list, tuple)):
raise ValueError("Data must be a single integer, or a bytearray,"
" list, or tuple.")
if key > self._max_size:
raise ValueError("Requested register '{0}' greater than maximum"
" FRAM size. ({1})".format(key,
self._max_size))
if not 0 < address < self._max_size:
raise ValueError("Address '{0}' out of range. It must be 0 <= address < {1}."
.format(address, self._max_size))

self._write(key, value, self._wraparound)
self._write(address, value, self._wraparound)

elif isinstance(key, slice):
elif isinstance(address, slice):
raise ValueError("Slicing not available during write operations.")

def _read_register(self, register, read_buffer):
Expand Down Expand Up @@ -237,21 +237,21 @@ def _write(self, start_register, data, wraparound=False):
else:
data_length = 1
data = [data]
if (start_register + data_length) - 1 > self._max_size:
if (start_register + data_length) > self._max_size:
if wraparound:
pass
else:
raise ValueError("Starting register + data length extends beyond"
" FRAM maximum size. Use ``write_wraparound`` to"
" FRAM maximum address. Use ``write_wraparound`` to"
" override this warning.")
with self._i2c as i2c:
for i in range(0, data_length):
if not (start_register + i) > self._max_size:
if not (start_register + i) > self._max_size - 1:
buffer[0] = (start_register + i) >> 8
buffer[1] = (start_register + i) & 0xFF
else:
buffer[0] = ((start_register + i) - self._max_size) >> 8
buffer[1] = ((start_register + i) - self._max_size) & 0xFF
buffer[0] = ((start_register + i) - self._max_size + 1) >> 8
buffer[1] = ((start_register + i) - self._max_size + 1) & 0xFF
buffer[2] = data[i]
i2c.write(buffer)

Expand Down Expand Up @@ -324,12 +324,12 @@ def _write(self, start_register, data, wraparound=False):
else:
data_length = 1
data = [data]
if (start_register + data_length) - 1 > self._max_size:
if (start_register + data_length) > self._max_size:
if wraparound:
pass
else:
raise ValueError("Starting register + data length extends beyond"
" FRAM maximum size. Use 'wraparound=True' to"
" FRAM maximum register. Use 'wraparound=True' to"
" override this warning.")
with self._spi as spi:
spi.write(bytearray([_SPI_OPCODE_WREN]))
Expand Down