The LPC47M233 is a 3.3V (Super I/O Block is 5V tolerant) PC2001 compliant Super I/O controller with an LPC interface and Hardware Monitoring capabilities. The LPC47M233 implements the LPC interface, a pin reduced ISA bus interface which provides the same or better performance as the ISA/X-bus with a substantial savings in pins used. This interface makes use of the PCI clock, which runs at 33MHz instead of the traditional 8MHz for the ISA bus, that eases some complications found in synchronous designs. In addition, all legacy drivers used for Super I/O components are still supported making this new interface transparent to the supporting software. The LPC bus also supports power management, such as wake-up and sleep modes, in the same way as the PCI bus. The LPC47M233 hardware-monitoring feature, which is accessible through the LPC interface, provides support for monitoring three external temperatures via thermal diode inputs and internal monitoring of its own HVCC power supply. It includes the capability of generating an interrupt to indicate out-of-limit temperature and voltage conditions via a dedicated interrupt pin. The LPC47M233 has incorporated the following Super I/O components: a parallel port; two serial ports; a keyboard/mouse controller; two floppy controllers, which use SMSC's true CMOS 765B core. In addition to the standard Super I/O components, this device offers two LED outputs, three fan control outputs, three tachometer inputs, and 37 General Purpose I/O control functions. Each fan control output may adjust the speed of one or more external fans using a pulse width modulation scheme. The tachometer inputs may be configured to monitor the speed of the fans whether they are controlled by a variable voltage or by a pulse width modulated input. The LPC47M233 is ACPI 2.0 compatible. The LPC47M233 supports the ISA Plug-and-Play standard register set (version 1.0a).