AS1108 查看數據表（PDF） - austriamicrosystems AG

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AS1108

4-Digit LED Display Driver

austriamicrosystems AG 

AS1108

Data Sheet

austriamicrosystems

Shutdown Mode

Shutdown Mode

The AS1108 features a shutdown mode, consuming only 10µA (max) current. Shutdown mode is entered via a write to

the Shutdown Register (see Table 7). At that point, all segment current sources are pulled to ground and all digit driv-

ers are connected to VDD, so that all segments are blanked.

Note: During shutdown mode the Digit-Registers maintain their data.

Shutdown mode can either be used as a means to reduce power consumption or for generating a flashing display

(repeatedly entering and leaving shutdown mode). For minimum supply current in shutdown mode, logic input should

be at GND or VDD (CMOS logic level).

The device needs typically 250µs to exit shutdown mode, and during shutdown mode the AS1108 is fully programma-

ble. Only the display test mode (see page 9) overrides shutdown mode.

When entering or leaving shutdown mode, the Feature Register is reset to its default values (all 0s) when Shutdown

Register bit D7 (page 8) = 0. When bit D7 = 1, the Feature Register is left unchanged when entering or leaving shut-

down mode.

Note: If the AS1108 is used with an external clock, Shutdown Register bit D7 should be set to 1 when writing to the

Shutdown Register.

Digit- and Control-Registers

The AS1108 contains four Digit-Registers and six control-registers, which are listed in Table 6. All registers are

selected using a 4-bit address word, and communication is done via the serial interface.

! Digit Registers – These registers are realized with an on-chip 32-bit memory. Each digit can be controlled directly

without rewriting the whole register contents.

! Control Registers – These registers consist of decode mode, display intensity, number of scanned digits, shut-

down, display test and features selection registers.

Table 6. Register Address Map

Register

No-Op

Digit 0

Address

HEX Code

D15:D12 D11

D10

D9

0xX0

X

0

0

0

0xX1

X

0

0

0

Digit 1

Digit 2

Digit 3

Decode-Mode

Intensity Control

Scan Limit

Shutdown

N/A

Feature

0xX2

0xX3

0xX4

0xX9

0xXA

0xXB

0xXC

0xXD

0xXE

X

0

0

1

X

0

0

1

X

0

1

0

X

1

0

0

X

1

0

1

X

1

0

1

X

1

1

0

X

1

1

0

X

1

1

1

Display Test

0xXF

X

1

1

1

Page

D8

0

11

1

N/A

0

N/A

1

N/A

0

N/A

1

8

0

10

1

10

0

8

1

N/A

0

11

1

9

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