#Bit bang spi arduino how to

Static char outputBuffer // outputBuffer likely 2x the size it needs to be. Then below, device address is optional 2nd parameter to the constructor fn. Assign each chip a unique 3-bit device address (by setting the A2,A1,A0 pins) Up to 8 MCP23S17 devices can share the same SPI bus and slave select pins. #define MCP23S17_SLAVE_SELECT_PIN 6 //arduino SPI Slave Select -> CS (Pin 11 on MCP23S17 DIP) Then choose any other free pin as the Slave Select (pin 10 if the default but doesn't have to be) #define SPI_CLOCK 8 //arduino SPI Slave Clock Input -> SCK (Pin 12 on MCP23S17 DIP) #define SPI_MISO not used 12 //arduino SPI Master In Slave Out -> SO (Pin 14 on MCP23S17 DIP) #define SPI_MOSI 7 //arduino SPI Master Out Slave In -> SI (Pin 13 on MCP23S17 DIP) Wire up the SPI Interface common lines: I would like to choose which pinout to utilize as well but am not sure how this would be coded.

#Bit bang spi arduino how to

However, I'm not sure how to modify or drive these 7-segement modules using the MCP23S17 chip.Ī skeleton script to display PI selected on pin 6 on the Uno and address 0x0 of the MCP23S17 is shown below. I realize I might have to modify the MAX7219 and bitBangedSPI libraries where the digitalWrite command is used. I have found the stackExchange entry How do you use SPI on an Arduino? to be helpful and this entry to be helpful, but all the examples just turn on LED lights, not digits of 7-segment led modules. The Mcp23s17 libraries to use might be or. I would like to extend the number of Slave Select (CS) choices by using the MCP23S17 chip.

I have used Nick Gammon's (MAX7219) and (bitBangedSPI) libraries to drive SPI 7-segment 8 digit led modules successfully from the Arduino Uno.