MOS Technology SPI

The 6529 Single Port Interface (SPI aka PIO) was an integrated circuit made by MOS Technology. It served as an I/O controller for the 6502 family of microprocessors, providing a single 8-bit digital bidirectional parallel I/O port. Unlike the more sophisticated 6522 VIA and 6526 CIA, it did not allow the data direction for each I/O line to be separately specified, nor did it support serial I/O or contain any timer capabilities. Because of this, it did not achieve widespread use.

6529 ICs were available in 1 MHz, 2 MHz, and 3 MHz versions. The form factor was a JEDEC-standard 20-pin ceramic or plastic DIP.

External links

• MOS 6529 datasheet (GIF format, zipped)

Interface chips from MOS Technology and second source/clone vendors

6520 PIA ● 6522 VIA ● 6523 TIA ● 6525 TPI ● 6526 CIA ● 6529 SPI ● 6530 RRIOT ● 6532 RIOT ● 6551 ACIA