AX68004LF datasheet(29/57 Pages) ASIX

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AX6800x

2/4-Port USB KVM Switch SoC

2.16 PS/2 Controller

The PS/2 Controller provides two independent PS/2 serial interfaces to the bidirectional protocol that can handle

data transmission between the host (PC) and the PS/2 device (Keyboard or Mouse). It also supports error detection

(for parity and stop bit) on all data received from PS/2 device and the timer control to timeout the device which

failed to respond and clock period.

2.17 USB Root Hub and Host Controller

The USB Host Controller built-in one root hub and provide 2/4 downstream ports to communication with

numerous USB full/low speed devices and compliant USB2.0 Full/Low speed standard, supporting data transfer at

full speed (12Mbit/s) and low speed (1.5 Mbit/s).

The USB Host Controller supports UHCI data transfer type schedule order to transfer Isochronous, Interrupt,

Control and Bulk data type, each packet type can be enabled or disabled by software commands. It also supports

one memory buffer to store receive or transfer data, and the memory buffer be divided to 3 memory area, namely,

ISTL, INTL and ATL, for four USB transfer type as above mention, each memory area also be divided to more

little buffer and it calls Transfer Descriptor (TD) structure. The total memory size is limited up to 4K bytes by Host

Control (HC) in 32KB Data SRAM.

The USB Host Controller supports 8 TDs for ISTL, 32 TDs for INTL and ATL in once transfer, the ISTL transfer

is also support automatic to synchronization one in advance assignment SOF interval per software assign, each

INTL TD also supports automatic interrupt polling rate to reduce CPU/software loading, the ATL supports two

different block size for control and bulk transfer enhancement memory used.

2.18 USB Device Controller

The AX6800x built-in 2/4 USB Device Controllers, compliant USB 2.0 Full-speed standard, supporting data

transfer at full speed (12Mbit/s) only.

The USB Device Controller supports 8 controllable Device Addresses and each Device Address supports 8

configurable Endpoints. Each Endpoint supports four kinds of transfer types, Control, Bulk, Interrupt and

Isochronous. AX6800x provides the programmable Maximum packet size and buffer Size for these transfer types.

The USB Device Controller can reference the Endpoint Index Table in xDATA memory for the pointer of the

Endpoint buffers to store the receiving/transmitting packet data to/from xDATA memory.

Each USB Device Controller integrated the controllable pull up resistance. It can be enabled when software

detected the VBUS supplied from external Host Controller (Attached) or disabled to disconnect the external Host

Device. Furthermore, the USB Device Controller also supports suspend function when bus idle over the

specification of USB standard and wakeup function for USB resume protocol, bus reset and cable plug/unplug.

The USB Device Controller responds the device status like USB bus status, endpoint transfer status, enhanced

IN-NAK status (responded the host when data not ready for IN transfer) for bulk transfer and other endpoint status

to CPU used by registers and interrupt. There is a 16-stage FIFO to record the endpoint transfer success status for

the interrupt status register. Software uses them to handle Endpoint transaction protocol with the external host

controller.

AX68004LF датащи(PDF) 29 Page - ASIX Electronics Corporation