LED Header

LED Header

Pinout

Pin

Description

1

Power

2

Ground

3

Drive activity

With firmware 1.18 (and above) the pin assignment is not static any more.

LED options

LED setting options
LED Options

Option

Description

On

LED always ON

Off

LED always OFF

Drive A Pwr

Power indicator of drive A

DrvAPwr + DrvBPwr

Power indicator of drive A and drive B combined

Drive A Act

LED ON when there is activity on drive A

DrvAAct + DrvBAct

LED ON, on activity of drive A and B combined

DrvAPwr ^ DrvAAct

Drive power LED XOR drive activity. This results in an inverse drive

activity, with similar dimming as the power LED has.

USB Activity

LED ON, on USB activity

Any Activity

LED ON, on any activity (exluding tape)

!(DrvAAct)

Inverse of drive A activity, so the LED will turn OFF on drive activity instead of ON

!(DrvAAct+DrvBAct)

Inverse of drive A and B combined, so LED will turn OFF on activity instead of ON

!(USB Act)

Inverse of USB Activity, so the LED will turn OFF on USB activity instead of ON

!(Any Act)

Inverse of Any Activity, so the LED will turn OFF on any activity instead of ON

IRQ Line

LED is ON when IRQ line is high (inactive)

!(IRQ Line)

Inverse of IRQ Line, so the LED is ON when IRQ line is low (active)

With the introduction of firmware 1.18 the behaviour of the LED can be changed.

What does !(option) mean?

As we can see in the table above, there are setting options (functions) that are noted as !(function). !(function) means it is an inverse outcome of a function.

We take a closer look at the function DrvAAct+DrvBAct. This means when there is drive A or drive B activity (combined) the LED will turn ON. So !(DrvAAct+DrvBAct) will do the opposite (inverse) of the function DrvAAct+DrvBAct, so the LED will turn OFF when there is activity on drive A or drive B.

Example with two separate LED’s

We are using a red and green LED, red will be the power LED (power) and green will be drive activity (drive). The power wire to the red led is connected to the Top pin (1) and the green led is connected to the Bottom pin (3), and of course the ground of both LED’s is connected to the ground pin (2).

Because there are two separate LED’s we want that the power is always ON, and the drive will only turn ON when there is activity.

LED setting options

So we use the following setting:

  • Power => LED Select Top: On

  • Drive => LED Select Bottom: DrvAAct+DrvBAct

To swap the color assignment, just swap the settings between Top and Bottom.

Example with duo LED

We are using a duo LED that has red and green combined in one package, red will be the power LED (power) and green will be drive activity (drive). The power wire to the red led is connected to the Top pin (1) and the green led is connected to the Bottom pin (3), and of course the ground of the LED is connected to the ground pin (2).

Because there is only “one” LED package we want that power will turn OFF when there is drive activity, or else the two colors will be mixed to yellow (red+green).

LED setting options

So we use the following setting:

  • Power => LED Select Top: !(DrvAAct+DrvBAct)

  • Drive => LED Select Bottom: DrvAAct+DrvBAct

To swap the color assignment, just swap the settings between Top and Bottom.

Technical information

Power LED

The power pin is provided with a 260KHz PWM signal, the PWM signal makes the LED less bright. The U64 has an on-board 220 ohms series resistor to lower the current, the supplied voltage 3.3V.

Drive activity LED

PWM

Description

Off

Drive Off

1/3

Drive On

2/3

Drive On + Floppy Mounted

3/3

Drive On + Floppy Mounted + Motor running

PWM = pulse width of the pwm signal.