AX68004LF datasheet(27/57 Pages) ASIX

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AX6800x

2/4-Port USB KVM Switch SoC

2.9 Power Management Unit

Table 2-1 below lists the 3 possible modes of operation of AX6800x, namely Full Speed mode, STOP mode, Deep

Sleep mode. For typical power consumption of AX6800x in these operation modes, please refer to Section 4.2.

Operation Mode

Description

Full Speed

The operating system clock of CPU and peripherals is running at full clock rate (i.e.,

48 or 96 MHz, depending on SYSCK_SEL setting).

STOP

The STOP mode is when CPU is in complete stop mode, the operating system clock of

CPU and peripherals is turned off, but the 12MHz crystal oscillation and 96MHz PLL

clock still run.

Deep Sleep

The Deep Sleep mode is when CPU is in complete stop mode, the operating system

clock of CPU and peripherals is turned off, and the 12MHz crystal oscillation and

96MHz PLL clock are turned off too.

Table 2-1: Three Power Management Operation Modes of AX6800x

2.10 Timers and Counters

The CPU of AX6800x provides three 16-bit timer/counters, namely, Timer 0, Timer 1, and a fully compatible with

the standard 8052 Timer 2, and one dedicated Millisecond Timer, which is programmable with 1ms resolution for

software use.

In the “timer mode”, timer registers are incremented in every 12 or 4 operating system clock periods when

appropriate timer is enabled. In the “counter mode”, the timer registers are incremented at every falling transition

on their corresponding input pins: TM0_CK, TM1_CK or TM2_CK. The input pins are sampled at every operating

system clock period.

2.11 UARTs

AX6800x supports 2 UART interfaces, namely, UART 0 and High Speed UART 1. The UART 0 has the same

functionality as standard 8051 UARTs and both support full duplex and receive double-buffered, meaning it can

commence reception of a second byte before a previously received byte has been read from the receive register.

The High Speed UART 1 of AX6800x is compatible with standard 16550 device architecture that provides serial

communication capabilities to communicate with Modem or other external device (e.g. computer) using RS-232 or

RS-485 protocols. The High Speed UART 1 supports transfer baud rate up to 921.6 Kbps, provides 16-byte

Transmitter and Receiver FIFO for data buffering, supports DMA mode burst transfer for data receive and transmit

process, and supports Auto-hardware flow control (Auto-RTS and Auto-CTS) and Auto-software flow control

(Auto-send and Auto-detect Xon and Xoff characters) to reduce CPU/software loading.

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