122 lines
4.6 KiB
Python
122 lines
4.6 KiB
Python
# The MIT License (MIT)
|
|
#
|
|
# Copyright (c) 2018 Dean Miller for Adafruit Industries
|
|
#
|
|
# Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
# of this software and associated documentation files (the "Software"), to deal
|
|
# in the Software without restriction, including without limitation the rights
|
|
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
# copies of the Software, and to permit persons to whom the Software is
|
|
# furnished to do so, subject to the following conditions:
|
|
#
|
|
# The above copyright notice and this permission notice shall be included in
|
|
# all copies or substantial portions of the Software.
|
|
#
|
|
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
# THE SOFTWARE.
|
|
"""
|
|
`adafruit_epd.mcp_sram` - Adafruit MCP SRAM - sram driver
|
|
====================================================================================
|
|
CircuitPython driver for Microchip SRAM chips
|
|
* Author(s): Dean Miller
|
|
"""
|
|
|
|
from micropython import const
|
|
from adafruit_bus_device import spi_device
|
|
|
|
__version__ = "0.0.0-auto.0"
|
|
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_EPD.git"
|
|
|
|
SRAM_SEQUENTIAL_MODE = const(1 << 6)
|
|
|
|
class Adafruit_MCP_SRAM_View:
|
|
"""A interface class that turns an SRAM chip into something like a memoryview"""
|
|
def __init__(self, sram, offset):
|
|
self._sram = sram
|
|
self._offset = offset
|
|
self._buf = [0]
|
|
|
|
def __getitem__(self, i):
|
|
return self._sram.read(self._offset+i, 1)[0]
|
|
|
|
def __setitem__(self, i, val):
|
|
self._buf[0] = val
|
|
self._sram.write(self._offset+i, self._buf)
|
|
|
|
class Adafruit_MCP_SRAM:
|
|
"""supporting class for communicating with
|
|
Microchip SRAM chips"""
|
|
SRAM_READ = 0x03
|
|
SRAM_WRITE = 0x02
|
|
SRAM_RDSR = 0x05
|
|
SRAM_WRSR = 0x01
|
|
|
|
def __init__(self, cs_pin, spi):
|
|
# Handle hardware SPI
|
|
self._spi = spi_device.SPIDevice(spi, cs_pin, baudrate=8000000)
|
|
self.spi_device = spi
|
|
self.cs_pin = cs_pin
|
|
self._buf = bytearray(3)
|
|
self._buf[0] = Adafruit_MCP_SRAM.SRAM_WRSR
|
|
self._buf[1] = 0x43
|
|
with self._spi as spidev:
|
|
spidev.write(self._buf, end=2) # pylint: disable=no-member
|
|
|
|
def get_view(self, offset):
|
|
"""Create an object that can be used as a memoryview, with a given offset"""
|
|
return Adafruit_MCP_SRAM_View(self, offset)
|
|
|
|
def write(self, addr, buf, reg=SRAM_WRITE):
|
|
"""write the passed buffer to the passed address"""
|
|
self._buf[0] = reg
|
|
self._buf[1] = (addr >> 8) & 0xFF
|
|
self._buf[2] = addr & 0xFF
|
|
|
|
with self._spi as spi:
|
|
spi.write(self._buf, end=3) # pylint: disable=no-member
|
|
spi.write(bytearray(buf)) # pylint: disable=no-member
|
|
|
|
def read(self, addr, length, reg=SRAM_READ):
|
|
"""read passed number of bytes at the passed address"""
|
|
self._buf[0] = reg
|
|
self._buf[1] = (addr >> 8) & 0xFF
|
|
self._buf[2] = addr & 0xFF
|
|
|
|
buf = bytearray(length)
|
|
with self._spi as spi:
|
|
spi.write(self._buf, end=3) # pylint: disable=no-member
|
|
spi.readinto(buf) # pylint: disable=no-member
|
|
return buf
|
|
|
|
def read8(self, addr, reg=SRAM_READ):
|
|
"""read a single byte at the passed address"""
|
|
return self.read(addr, 1, reg)[0]
|
|
|
|
def read16(self, addr, reg=SRAM_READ):
|
|
"""read 2 bytes at the passed address"""
|
|
buf = self.read(addr, 2, reg)
|
|
return buf[0] << 8 | buf[1]
|
|
|
|
def write8(self, addr, value, reg=SRAM_WRITE):
|
|
"""write a single byte at the passed address"""
|
|
self.write(addr, [value], reg)
|
|
|
|
def write16(self, addr, value, reg=SRAM_WRITE):
|
|
"""write 2 bytes at the passed address"""
|
|
self.write(addr, [value >> 8, value], reg)
|
|
|
|
def erase(self, addr, length, value):
|
|
"""erase the passed number of bytes starting at the passed address"""
|
|
self._buf[0] = Adafruit_MCP_SRAM.SRAM_WRITE
|
|
self._buf[1] = (addr >> 8) & 0xFF
|
|
self._buf[2] = addr & 0xFF
|
|
fill = bytearray([value])
|
|
with self._spi as spi:
|
|
spi.write(self._buf, end=3) # pylint: disable=no-member
|
|
for _ in range(length):
|
|
spi.write(fill) # pylint: disable=no-member
|