If anyone decides to do the counter replacement (see Downloads (http://www.bavariayacht.info/downloads.htm) page) please don't throw away the old LCD, I need one to do some tests.
Hi All - does anyone know where the data (hours) is stored and when the LCD display is replaced will it read zero of the accumulated hours.
Cheers
RW
Quote from: aquapore on June 17 2014, 12:47
Hi All - does anyone know where the data (hours) is stored and when the LCD display is replaced will it read zero of the accumulated hours.
If you replace it with a standalone unit, then yes it will be zero.
As to where it is stored ...
Like many people I had to replace my VDO tachometer hour counter, but this makes changing the division ratio almost impossible so I've bought a replacement. I've been delving a bit into the electronics, two main reasons:
[1] To read the hour value on the original
[2] To set the hour value on the replacement unit without running it for 1000+ hours
I have discovered that the PCB has a Philips EEPROM PCF8582C, which is where they store the hour data, as well as the division ratio etc.
(http://i77.photobucket.com/albums/j54/nigelmercier/8582C-LR_zps07ac6d44.png~original)
See datasheet: www.nxp.com/documents/data_sheet/PCF8582C_2.pdf (http://www.nxp.com/documents/data_sheet/PCF8582C_2.pdf)
I think it should be possible to read (and possibly write to) this IC in-situ, it has an I
2C-bus interface.
There is also a 6-way FFC socket to the LCD glass, or the connector pins are easily accessible on the rear. Reading the data here would at least give me [1].
To save me reinventing the wheel, has anyone played around with the I
2C bus? I was going to play with my Bus Pirate first: http://amzn.to/1eB6yxg (http://amzn.to/1eB6yxg)
[Later] I swapped the EEPROM from my old unit to the replacement, the hour counter was restored to the correct value.