store rtc time offset

protocol.py

@@ -35,6 +35,13 @@ class I2CPCClient:
         payload = bytes([2, addr, len(write_data)]) + write_data + bytes([read_len])
         return self._send_packet(payload)
     
+    def write_eeprom(self, addr: int, data: bytes):
+        payload = bytes([7, (addr >> 8) & 0xff, addr & 0xff]) + data
+        return self._send_packet(payload)
+    def read_eeprom(self, addr: int, len: int):
+        payload = bytes([8, (addr >> 8) & 0xff, addr & 0xff, len])
+        return self._send_packet(payload)
+
     def version(self): return self._send_packet(bytes([4]))
 
     def quit(self): return self._send_packet(bytes([3]))

rtc.py

@@ -2,10 +2,16 @@ import datetime
 from protocol import I2CPCClient
 
 def sync_rtc(p: I2CPCClient):
+    TIMEOFFSET_ADDR = 2275
+    dtime = datetime.datetime.now(datetime.UTC)
+
+    utc_off = d.total_seconds() / 3600 if (d := datetime.datetime.now().astimezone().utcoffset()) else 0
+    if(p.version()[-1] >= 2): p.write_eeprom(TIMEOFFSET_ADDR, int(utc_off).to_bytes(1, signed=True))
+    else: dtime = datetime.datetime.now()
+
     ADDRESS = 0x32
     p.write_i2c(ADDRESS, b"\x1f\x40") # halt the clock
     
-    dtime = datetime.datetime.now()
     def toBCD(val: int) -> int:
         return ((val // 10) << 4) | (val % 10)
     data = b"\x10"
@@ -19,3 +25,8 @@ def sync_rtc(p: I2CPCClient):
     p.write_i2c(ADDRESS, data)
     
     p.write_i2c(ADDRESS, b"\x1f\x00") # start the clock
+
+p = I2CPCClient("COM17")
+sync_rtc(p)
+p.reboot()
+p.close()