14-02-2018, 23:45
[attachment=1317 Wrote:Werk_AG pid='8888' dateline='1518633182']Usually I don't do any bridges at A0, A1 or A2. Without any bridges, the I2C address is 0x27 (at least for all the back pack modules I have seen), which is the default address defined on the software.
Werk,
As mentioned i have an issue with two 20 x 4 LCD displays.
The top one in the photo was purchased as an I2C compatible device and works well with the address of 0x3F (chip is PCF 8574AT).
The lower one is one of two purchased as serial models and I attached the I2C boards myself, both have the same 8574AT chip but neither will work regardless of address used.
The only difference appears to be that the non working boards do not have capacitors C1 and C2 fitted
Any ideas?
Jim