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www.diodes.com

April 2019

Diodes Incorporated

PI7C9X752

Document Number DS40312 Rev 3-2

A product Line of

Diodes Incorporated

PI7C9X752

Functional Description

The PI7C9X752 integrates the functions of 4 enhanced 16C550 UARTs. Each UART channel has its own 16C550 UART compatible

configuration register set for individual channel control, status, and data transfer. Additionally, each UART channel has 64-byte

of transmit and receive FIFOs, automatic RTS/CTS hardware flow control with hysteresis control, automatic Xon/Xoff and special

character software flow control, programmable transmit and receive FIFO trigger levels, FIFO level counters, infrared encoder and

decoder (IrDA ver. 1.0 and 1.1), programmable baud rate generator with a prescaler of divide by 1 or 4, and data rate up to 16Mbps

with 4X sampling clock. The PI7C9X752 is a 1.62-3.6V device with 5 volt tolerant inputs (except XTAL1).

The PI7C9X752 comes with packages: 48-pin QFP which offer both Intel and Motorola interface.

1. Trigger Levels

The PI7C9X752 provides independent selectable and programmable trigger levels for both Receiver and transmitter DMA and inter-

rupt generation. After reset, both transmitter and receiver FIFOs are disabled and so, in effect, the trigger level is the default value of

one character. The selectable trigger levels are controlled via Register TLR (if TLR is non-zero) or (if TLR is zero) via FIFO Control

Register (FCR) and Feature Control Register(FCTR). Refer to Table 1.

Table 1. Transmit and Receive FIFO Trigger Table and Level Selection

Trigger

FCTR

BIT-5

FCTR

BIT-4

FCR

BIT-7

FCR

BIT-6

FCR

BIT-5

FCR

BIT-4

Receive Trigger Level Transmit Trigger

Level

Table-A

0

0

0

0

1

1

0

1

0

1

0

0

1(Default)

4

8

14

1(Default)

Table-B

0

1

0

0

1

1

0

1

0

1

0

0

1

1

0

1

0

1

8

16

24

28

16

8

24

30

Table-C

1

0

0

0

1

1

0

1

0

1

0

0

1

1

0

1

0

1

8

16

56

60

8

16

32

56

Table-D

1

1

X

X

X

X

Programmable via RX-

TRG register

Programmable via TX-

TRG register