Merge pull request peterhinch#22 from adeuring/master

Add support for I2C EEPROMs with page sizes other than 128 in eeprom_…

Author: peterhinch

eeprom/i2c/I2C.md

@@ -132,6 +132,7 @@ Arguments:
  is `2**block_size` so is 512 bytes by default.
  5. `addr` override base address for first chip
  6. `max_chips_count` override max_chips_count
+ 7. `page_size=7` The binary logarithm of the page size of the EEPROMs, i.e., the page size in bytes is `2 ** page_size`. The page size may vary between chips from different manufacturers even for the same storage size. Note that specifying a too large value will most likely lead to data corruption in write operations. Look up the correct value for your setup in the chip's datasheet.
 
  With `addr` and `max_chips_count` override, it's possible to make multiple
  configuration

eeprom/i2c/eep_i2c.py

@@ -132,8 +132,10 @@ def cptest(eep=None):  # Assumes pre-existing filesystem of either type
             print("Fail mounting device. Have you formatted it?")
             return
         print("Mounted device.")
-    cp("eep_i2c.py", "/eeprom/")
-    cp("eeprom_i2c.py", "/eeprom/")
+    cp(__file__, "/eeprom/")
+    # We may have the source file or a precompiled binary (*.mpy)
+    suffix = __file__[__file__.rfind('.'):]
+    cp("eeprom_i2c" + suffix, "/eeprom/")
     print('Contents of "/eeprom": {}'.format(uos.listdir("/eeprom")))
     print(uos.statvfs("/eeprom"))
 

eeprom/i2c/eeprom_i2c.py

@@ -19,7 +19,7 @@
 # Logical EEPROM device consists of 1-8 physical chips. Chips must all be the
 # same size, and must have contiguous addresses.
 class EEPROM(BlockDevice):
-    def __init__(self, i2c, chip_size=T24C512, verbose=True, block_size=9, addr=_ADDR, max_chips_count=_MAX_CHIPS_COUNT):
+    def __init__(self, i2c, chip_size=T24C512, verbose=True, block_size=9, addr=_ADDR, max_chips_count=_MAX_CHIPS_COUNT, page_size=7):
         self._i2c = i2c
         if chip_size not in (T24C32, T24C64, T24C128, T24C256, T24C512):
             print("Warning: possible unsupported chip. Size:", chip_size)
@@ -29,6 +29,8 @@ def __init__(self, i2c, chip_size=T24C512, verbose=True, block_size=9, addr=_ADD
         self._i2c_addr = 0  # I2C address of current chip
         self._buf1 = bytearray(1)
         self._addrbuf = bytearray(2)  # Memory offset into current chip
+        self._page_size = 2 ** page_size
+        self._page_mask = ~(self._page_size - 1)
 
     # Check for a valid hardware configuration
     def scan(self, verbose, chip_size, addr, max_chips_count):
@@ -67,7 +69,7 @@ def _getaddr(self, addr, nbytes):  # Set up _addrbuf and _i2c_addr
         self._addrbuf[0] = (la >> 8) & 0xFF
         self._addrbuf[1] = la & 0xFF
         self._i2c_addr = self._min_chip_address + ca
-        pe = (addr & ~0x7F) + 0x80  # byte 0 of next page
+        pe = (addr & self._page_mask) + self._page_size  # byte 0 of next page
         return min(nbytes, pe - la)
 
     # Read or write multiple bytes at an arbitrary address