Figure 1 shows a typical converter schematic. The I2C bus is connected to PIN5 and PIN6, and the SPI bus is connected to PIN9, PIN10, PIN11, and PIN12. PIN8 is used to control the transmission ...

[Tom] needed 8 displays for a project. He wanted to to control them over I2C, and was trying to reduce cost. Some vendors make I2C controllable seven segment displays, but they cost about $10 each.

If you can't pick up the schematic and know (at a moderately high level) what the design is supposed to do and how it is supposed to do it, then you have not really done your job as the designer. The ...