[Figure 1, callout 34]
The VMK180 cooling fan connector is shown in the following figure. The VMK180 uses the Maxim MAX6643 (U64) fan controller, which autonomously controls the fan speed by controlling the pulse width modulation (PWM) signal to the fan based on the die temperature sensed via the Versal device's DXP and DXN pins. The fan rotates slowly (acoustically quiet) when the Versal device's U1 is cool and rotates faster as the device heats up (acoustically noisy).
The fan speed (PWM) versus the Versal device die temperature algorithm along with the over temperature set point and fan failure alarm mechanisms are defined by the strapping resistors on the MAX6643 device.
The over temperature and fan failures alarms can be monitored either by any available processor in the Versal device's U1 by polling the I2C expander U233 on the I2C bus or via the ZU4 U125 System Controller.
The VMK180 board provides a fan controller bypass header J234 to permit the fan to be always on. Always on (J234 pins 2 and 3 jumpered) is the default jumper setting shown in the figure.
