PIC Tutorial - I2C A2D Board
I2C A2D Board
This is the I2C A2D (Analogue to Digital converter) Board, it uses a Philips PCF8591P, which is an I2C chip providing 4 analogue inputs, and 1 analogue output, all having 8 bit resolution. There are actually very few support components required, I've chosen to use an external 2.5V precision voltage reference, which feeds in at pin 14, but this could be simply connected to the 5V rail - though it would be less accurate. By using the 2.5V reference we set the range of the conversion from 0-2.5V, however this can easily be scaled by feeding from a suitable attenuator. Notice the circuit also shows an EEPROM, the idea being to give the option of storing samples in it's non-volatile memory, and I'll be using a 24C256 to give 32,768 bytes of storage. Notice both chips connect to the same port pins via the I2C bus - by having different chip addresses we can address either one independently.
Although it's labelled as connecting to PortB, as with most of the boards, it can also be connected to PortA if required.