AT89C5131A-L View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89C5131A-L

8-bit Flash Microcontroller with Full Speed USB Device

Atmel Corporation 

Table 8. Ports Signal Description

Signal

Name

P0[7:0]

Type Description

Port 0

P0 is an 8-bit open-drain bidirectional I/O port. Port 0

I/O

pins that have 1s written to them float and can be used

as high impedance inputs. To avoid any parasitic current

consumption, Floating P0 inputs must be pulled to VDD or

VSS.

P1[7:0]

I/O

Port 1

P1 is an 8-bit bidirectional I/O port with internal pull-ups.

P2[7:0]

I/O

Port 2

P2 is an 8-bit bidirectional I/O port with internal pull-ups.

P3[7:0]

I/O

Port 3

P3 is an 8-bit bidirectional I/O port with internal pull-ups.

P4[1:0]

I/O

Port 4

P4 is an 2-bit open port.

Alternate Function

AD[7:0]

KIN[7:0]

T2

T2EX

ECI

CEX[4:0]

A[15:8]

LED[3:0]

RxD

TxD

INT0

INT1

T0

T1

WR

RD

SCL

SDA

Table 9. Clock Signal Description

Signal

Name Type Description

Alternate

Function

Input to the on-chip inverting oscillator amplifier

XTAL1

I To use the internal oscillator, a crystal/resonator circuit is connected to this

-

pin. If an external oscillator is used, its output is connected to this pin.

Output of the on-chip inverting oscillator amplifier

XTAL2 O To use the internal oscillator, a crystal/resonator circuit is connected to this

-

pin. If an external oscillator is used, leave XTAL2 unconnected.

PLL Low Pass Filter input

PLLF

I Receives the RC network of the PLL low pass filter (See Figure 4 on page

-

11 ).

8 AT89C5131A-L

4338E–USB–06/06

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