Interfacing Raspberry Pi with MCP3208 ADC

Raspberry Pi Model B has SPI pins extended to the GPIO connector with reference designator J8. We can see the SPI pins - MOSI on PIN#19, MISO on PIN#21, SCLK on PIN#23 and Chip Select CE0 on PIN#24

MCP3208 is 8-channel 12-bit ADC converter from Microchip. MCP3208 has SPI interface which helps to read the ADC values input to the channels 0-7. MCP3208 operates between 2.7V to 5.5V supply. Here we are showing the pinout of MCP3208. On the board, VREF is shorted to VDD, so supplying VDD supplies the VREF as well.

Let us know look at the pins that are connected between Raspberry Pi and MCP3208. As the Raspberry Pi pins are 3.3V logic levels, we are connecting the MCP3208 to 3.3V as well. Ground is made common between the boards. MOSI of Raspberry Pi is connected to DIN of MCP3208. MISO of Raspberry Pi is connected to DOUT of MCP3208.