#00-2, M1S: Three Direct I/O Lines and Ground


Function: Three directly exposed I/O lines of the microcontroller plus the ground line

Form factor: M1S

Category: Blank module

Special needs: ---

Power requirements: 5V/20mA

Mates with: #19, #20, #21

See also: #00-1, #00-3



As with Tibbit #00-1, this device allows you to work with CPU lines directly. The only difference is that one of the lines is replaced by the ground (GND) line.

The GND line may be necessary when using this Tibbit with "C" device #21 (four terminal blocks). #21 doesn't have its own dedicated ground, so if the ground is necessary (and it usually is) then it must come from the neighboring "M" device, such as this Tibbit.

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.


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