Fixing bugs in the i2c wrapper, noting limitations on period

Author: Kevin J Walters

microbit/serial-periodic-print-mcp7940.py

@@ -1,76 +1,76 @@
-### serial-periodic-print-mcp9740 v1.1
-
-### copy this file to BBC micro:bit V2 as main.py
-
-### MIT License
-
-### Copyright (c) 2025 Kevin J. Walters
-
-### 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.
-
-
-import gc
-
-import mcp7940
-
-from microbit import i2c
-from utime import ticks_us, ticks_diff, ticks_add
-
-## PERIOD_US = 60 * 60 * 1000 * 1000
-## PERIOD_US = 10 * 1000 * 1000
-PERIOD_US = 1 * 1000 * 1000
-
-
-class EnhancedI2C:
-    def __init__(self, i2c):
-        self._i2c = i2c
-
-    def readfrom_mem(self, addr, memaddr, nbytes, *, addrsize=8):
-        i2c.write(addr, bytes([memaddr]))
-        return(i2c.read(addr, nbytes))
-
-    def readfrom_mem_into(self, addr, memaddr, buf, *, addrsize=8):
-        raise NotImplementedError
-    
-    def writeto_mem(self, addr, memaddr, buf, *, addrsize=8):
-        i2c.write(addr, bytes([memaddr]) + buf)
-
-
-ei2c = EnhancedI2C(i2c)
-mcp = mcp7940.MCP7940(ei2c)
-mcp.set_trim(0)
-mcp.time = (2025, 1, 1, 00, 00, 00, 2, 1)
-mcp.start()
-
-last_print_us = None
-timestamp_us = None
-uncollected = True
-
-gc.collect()
-last_print_us = ticks_us()
-while True:    
-    timestamp_us = ticks_us()
-    if ticks_diff(timestamp_us, last_print_us) >= PERIOD_US:
-        print(timestamp_us, ticks_us(), *mcp.time, sep=",")
-        ### Don't assign timestamp_us here in case it has slipped a little
-        last_print_us = ticks_add(last_print_us, PERIOD_US)
-        uncollected = True
-    elif uncollected:
-        gc.collect()
-        uncollected = False
+### serial-periodic-print-mcp9740 v1.2
+
+### copy this file to BBC micro:bit V2 as main.py
+
+### MIT License
+
+### Copyright (c) 2025 Kevin J. Walters
+
+### 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.
+
+
+import gc
+
+import mcp7940
+
+from microbit import i2c
+from utime import ticks_us, ticks_diff, ticks_add
+
+### This will work for up to 6 minutes with ticks_us/ticks_diff
+PERIOD_US = 6 * 60 * 1000 * 1000
+## PERIOD_US = 10 * 1000 * 1000
+##PERIOD_US = 1 * 1000 * 1000
+
+class EnhancedI2C:
+    def __init__(self, i2c_):
+        self._i2c = i2c_
+
+    def readfrom_mem(self, addr, memaddr, nbytes, *, addrsize=8):
+        self._i2c.write(addr, bytes([memaddr]))
+        return self._i2c.read(addr, nbytes)
+
+    def readfrom_mem_into(self, addr, memaddr, buf, *, addrsize=8):
+        raise NotImplementedError
+
+    def writeto_mem(self, addr, memaddr, buf, *, addrsize=8):
+        self._i2c.write(addr, bytes([memaddr]) + buf)
+
+
+ei2c = EnhancedI2C(i2c)
+mcp = mcp7940.MCP7940(ei2c)
+mcp.set_trim(0)
+mcp.time = (2025, 1, 1, 00, 00, 00, 2, 1)
+mcp.start()
+
+last_print_us = None
+timestamp_us = None
+uncollected = False
+
+gc.collect()
+last_print_us = ticks_us()
+while True:
+    timestamp_us = ticks_us()
+    if ticks_diff(timestamp_us, last_print_us) >= PERIOD_US:
+        print(timestamp_us, ticks_us(), *mcp.time, sep=",")
+        ### Don't assign timestamp_us here in case it has slipped a little
+        last_print_us = ticks_add(last_print_us, PERIOD_US)
+        uncollected = True
+    elif uncollected:
+        gc.collect()
+        uncollected = False