FDC37B78X 데이터 시트보기 (PDF) - SMSC -> Microchip

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FDC37B78X

Enhanced Super I/O Controller with ACPI Support, Real Time Clock and Consumer IR

SMSC -> Microchip 

Host-to-CPU Communication

The host system can send both commands and

data to the Input Data register. The CPU

differentiates between commands and data by

reading the value of Bit 3 of the Status register.

When bit 3 is "1", the CPU interprets the register

contents as a command. When bit 3 is "0", the

CPU interprets the register contents as data.

During a host write operation, bit 3 is set to "1" if

SA2 = 1 or reset to "0" if SA2 = 0.

KIRQ

If "EN FLAGS" has been executed and P24 is

set to a one: the OBF flag is gated onto KIRQ.

The KIRQ signal can be connected to system

interrupt to signify that the FDC37B78x CPU has

written to the output data register via "OUT

DBB,A". If P24 is set to a zero, KIRQ is forced

low. On power-up, after a valid RST pulse has

been delivered to the device, KIRQ is reset to 0.

KIRQ will normally reflects the status of writes

"DBB". (KIRQ is normally selected as IRQ1 for

keyboard support.)

If "EN FLAGS” has not been executed: KIRQ

can be controlled by writing to P24. Writing a

zero to P24 forces KIRQ low; a high forces

KIRQ high.

MIRQ

If "EN FLAGS" has been executed and P25 is

set to a one:; IBF is inverted and gated onto

MIRQ. The MIRQ signal can be connected to

system interrupt to signify that the FDC37B78x

CPU has read the DBB register.

EXTERNAL KEYBOARD AND MOUSE

INTERFACE

Industry-standard PC-AT-compatible keyboards

employ a two-wire, bidirectional TTL interface

for data transmission. Several sources also

supply PS/2 mouse products that employ the

same type of interface. To facilitate system

expansion, the FDC37B78x provides four signal

pins that may be used to implement this

interface directly for an external keyboard and

mouse.

The FDC37B78x has four high-drive, open-drain

output, bidirectional port pins that can be used

for external serial interfaces, such as ISA

external keyboard and PS/2-type mouse

interfaces. They are KCLK, KDAT, MCLK, and

MDAT. P26 is inverted and output as KCLK.

The KCLK pin is connected to TEST0. P27 is

inverted and output as KDAT. The KDAT pin is

connected to P10. P23 is inverted and output as

MCLK. The MCLK pin is connected to TEST1.

P22 is inverted and output as MDAT. The

MDAT pin is connected to P11. NOTE: External

pull-ups may be required.

KEYBOARD POWER MANAGEMENT

The keyboard provides support for two power-

saving modes: soft powerdown mode and hard

powerdown mode. In soft powerdown mode,

the clock to the ALU is stopped but the

timer/counter and interrupts are still active. In

hard power down mode the clock to the 8042 is

stopped.

If "EN FLAGS” has not been executed, MIRQ is

controlled by P25, Writing a zero to P25 forces

MIRQ low, a high forces MIRQ high. (MIRQ is

normally selected as IRQ12 for mouse support).

Gate A20

A general purpose P21 is used as a software

controlled Gate A20 or user defined output.

Soft Power Down Mode

This mode is entered by executing a HALT

instruction. The execution of program code is

halted until either RESET is driven active or a

data byte is written to the DBBIN register by a

master CPU. If this mode is exited using the

interrupt, and the IBF interrupt is enabled, then

program execution resumes with a CALL to the

interrupt routine, otherwise the next instruction

is executed. If it is exited using RESET then a

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