Four direct I/O lines

Four directly exposed I/O lines of the microcontroller.

Form: M1S
  • 5V - Consumes 20mA
Mates with: #20, #21, #49


Sometimes you just want to work with CPU I/O lines directly — no logic or circuitry in between. This Tibbit is (basically) four wires that connect its control lines to I/O lines. Complement it with terminal block Tibbit #20 (nine terminal blocks) or #21 (four terminal blocks) and you have four CPU lines "exposed" and ready to be used.

Note that a CPU I/O line has the voltage swing from 0-3.3V when the line is enabled (io.enabled= 1- YES). The voltage may be close to 5V when the line is disabled (io.enabled= 0- NO). This is because the CPU has weak pull-up resistors connected to 5V.

Combining this Tibbit with #21 is potentially limited in use because #00-1 doesn't have dedicated ground or power lines, and Tibbit #21 doesn't have them, either. Need ground (and power)? Consider replacing #21 with #20 (it has ground and power), or turn to using Tibbit #00-2 (it provides ground) or #00-3 (it provides ground and power).


Four yellow LEDs are connected to four control lines of the CPU (through buffering gates). LEDs light up for the LOW state of control lines.