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www.diodes.com

April 2019

Diodes Incorporated

PI7C9X760

Document Number DS40305 Rev 6-2

A product Line of

Diodes Incorporated

PI7C9X760

Offset 01H: Divisor Latch MSB(DLH). Accessible when LCR[7]=1 and LCR!=0xBF. Default=00

Bit

Type

Description

[7:0]

RW

MSB bits of divisor for baud rate generator.

Note: It is reset only when Power-On-Reset.

Offset 02H: Interrupt Identification Register (IIR). Accessible when LCR[7]=0. Default=01

Bit

Type

Description

[7:6]

RO

Mirror the content of FCR[0]

[5:1]

RO

5-bit encoded interrupt.

0

RO

Interrupt status. "1": No interrupt is pending.

"0": An interrupt is pending.

Priority Level

IIR[5]

IIR[4]

IIR[3]

IIR[2]

IIR[1]

IIR[0]

Source of Interrupt

1

0

0

0

1

1

0

Receive Line Status Error

2

0

0

1

1

0

0

Receiver timeout

2

0

0

0

1

0

0

RHR interrupt

3

0

0

0

0

1

0

THR interrupt

4

0

0

0

0

0

0

Modem interrupt

5

1

1

0

0

0

0

Input pin change of state

6

0

1

0

0

0

0

Rx Xoff signal/special character

7

1

0

0

0

0

0

CTS,RTS change from active to inactive

Note: IIR[4] is cleared by Xon detection if the interrupt is caused by Xoff detection, or cleared by a read of the IIR if it is caused by special char detection.

Offset 02H: FIFO Control Register (FCR). Accessible when LCR[7]=0. Default=00

Bit

Type

Description

[7:6]

WO

RX trigger. Sets the trigger level for the RX FIFO

00 = 8 characters

01 = 16 characters

10 = 56 characters

11 = 60 characters

[5:4]

WO

TX trigger. Sets the trigger level for the TX FIFO

00 = 8 spaces

01 = 16 spaces

10 = 32 spaces

11 = 56 spaces

3

RO

Reserved

2

WOS

Reset TX FIFO.

0 = No FIFO transmit reset

1 = Clears the contents of Tx FIFO and resets the FIFO level logic.

TSR is not cleared. This bit will return to logic 0 after clearing the FIFO

1

WOS

Reset RX FIFO.

0 = No FIFO receive reset

1 = Clears the contents of Rx FIFO and resets the FIFO level logic.

RSR is not cleared. This bit will return to logic 0 after clearing the FIFO

Configuration Registers cont..