LEDs and LED Lines

The EM1001 has three onboard LEDs:

Further information on status LEDs can be found in Status LEDs.

The EM1001 also has two control lines — Status Green (SG) and Status Red (SR) — for connecting to external green and red status LEDs. These external LEDs work in parallel with the onboard LEDs. As the maximum sink current of an I/O line is 10mA and the onboard LEDs already consume around 7mA, externally connected LEDs must consume less than 3mA of current. Connect external SR and SG LEDS through buffers (logic gates) if a higher current is desired. The SG and SR lines are active LOW (i.e., an LED must turn on when its control line is at LOW). Take this into consideration when designing the LED circuit.  

Your Tibbo BASIC/C application can control the red and green status LEDs, as well as up to four externally connected LED pairs, through the pat. object.