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AS1118

Datasheet - D e t a i l e d D e s c r i p t i o n

Note: Write operation: D14=0; Read operation: D14=1.

The Shutdown Register controls AS1118 shutdown mode.

Decode Enable Register (0x09)

The Decode Enable Register sets the decode mode. BCD/HEX decoding (either BCD code – characters 0:9, E, H, L,

P, and -, or HEX code – characters 0:9 and A:F) is selected by bit D2 (page 14) of the Feature Register. The Decode

Enable Register is used to select the decode mode or no-decode for each digit. Each bit in the Decode Enable Regis-

ter corresponds to its respective display digit (i.e., bit D0 corresponds to digit 0, bit D1 corresponds to digit 1 and so

on). Table 11 lists some examples of the possible settings for the Decode Enable Register bits.

Note: A logic high enables decoding and a logic low bypasses the decoder altogether.

When decode mode is used, the decoder looks only at the lower-nibble (bits D3:D0) of the data in the Digit-Registers,

disregarding bits D6:D4. Bit D7 sets the decimal point (SEG DP) independent of the decoder and is positive logic (bit

D7 = 1 turns the decimal point on). Table 11 lists the code-B font; Table 12 lists the HEX font.

When no-decode mode is selected, data bits D7:D0 of the Digit-Registers correspond to the segment lines of the

AS1118. Table 13 shows the 1:1 pairing of each data bit to the appropriate segment line.

Diagnostic Digit 0

X

1

0

1

0

1

0

0

N/A

Diagnostic Digit 1

X

1

0

1

0

1

0

1

N/A

Diagnostic Digit 2

X

1

0

1

0

1

1

0

N/A

Diagnostic Digit 3

X

1

0

1

0

1

1

1

N/A

Diagnostic Digit 4

X

1

0

1

1

0

0

0

N/A

Diagnostic Digit 5

X

1

0

1

1

0

0

1

N/A

Diagnostic Digit 6

X

1

0

1

1

0

1

0

N/A

Diagnostic Digit 7

X

1

0

1

1

0

1

1

N/A

Table 9. Shutdown Register Format (Address (HEX) = 0x0C))

Mode

HEX

Code

Register Data

D7

D6 D5 D4

D3 D2

D1 D0

Shutdown Mode, Reset Feature Register to Default Settings

0x00

0

X

X

X

X

X

X

0

Shutdown Mode, Feature Register Unchanged

0x80

1

X

X

X

X

X

X

0

Normal Operation, Reset Feature Register to Default Settings

0x01

0

X

X

X

X

X

X

1

Normal Operation, Feature Register Unchanged

0x81

1

X

X

X

X

X

X

1

Table 10. Decode Enable Register Format Examples

Decode Mode

HEX

Code

Register Data

D7 D6 D5 D4 D3 D2 D1 D0

No decode for digits 7:0

0x00

0

0

0

0

0

0

0

0

Code-B/HEX decode for digit 0. No decode for digits 7:1

0x01

0

0

0

0

0

0

0

1

Code-B/HEX decode for digit 0:2. No decode for digits 7:3

0x07

0

0

0

0

0

1

1

1

Code-B/HEX decode for digits 0:5. No decode for digits 7:6

0x3F

0

0

1

1

1

1

1

1

Code-B/HEX decode for digits 0,2,5. No decode for digits 1, 3, 4, 6, 7

0x25

0

0

1

0

0

1

0

1

Table 8. Register Address Map

Register

Address

Page

D15

D14

D13

D12

D11

D10

D9

D8

D7:D0