Data Sheet

www.austriamicrosystems.com/LED-Driver-ICs/AS1115 Revision 1.08 17 - 25

AS1115

Datasheet - D e t a iled D e s c r iptio n

Display brightness is controlled by an integrated pulse-width modulator which is controlled by the lower-nibble of the Intensity Control Register.

The modulator scales the average segment-current in 16 steps from a maximum of 15/16 down to 1/16 of the peak current set by RSET.

Scan-Limit Register (0x0B)

The Scan-Limit Register controls which of the digits are to be displayed. When all 8 digits are to be displayed, the update frequency is typically

0Hz. If the number of digits displayed is reduced, the update frequency is increased. The frequency can be calculated using 10 x fOSC/(N+2),

where N is the number of digits.

Note: To avoid differences in brightness this register should not be used to blank parts of the display (leading zeros).

Table 17. Intensity Register Format

Duty Cycle HEX Code

MSB D2 D1 LSB MSB D2 D1 LSB

1/16 (min on) 0xX0 0 0 0 0 9/16 0xX8 1 0 0 0

2/16 0xX1 0 0 0 1 10/16 0xX9 1 0 0 1

3/16 0xX2 0 0 1 0 11/16 0xXA 1 0 1 0

4/16 0xX3 0 0 1 1 12/16 0xXB 1 0 1 1

5/16 0xX4 0 1 0 0 13/16 0xXC 1 1 0 0

6/16 0xX5 0 1 0 1 14/16 0xXD 1 1 0 1

7/16 0xX6 0 1 1 0 15/16 0xXE 1 1 1 0

8/16 0xX7 0 1 1 1 15/16 (max on) 0xXF 1 1 1 1

Table 18. Intensity Register Address

Type D7:D4 D3:D0

0x0A Global X Global Intensity

0x10 Digit Digit 1 Intensity Digit 0 Intensity

0x11 Digit Digit 3 Intensity Digit 2 Intensity

0x12 Digit Digit 5 Intensity Digit 4 Intensity

0x13 Digit Digit 7 Intensity Digit 6 Intensity

Table 19. Scan-Limit Register Format (Address (HEX) = 0x0B))

Scan Limit

HEX

Code

Scan Limit

HEX

Code

D7:D3 D2 D1 D0 D7:D3 D2 D1 D0

Display digit 0 only 0xX0 X 0 0 0 Display digits 0:4 0xX4 X 1 0 0

Display digits 0:1 0xX1 X 0 0 1 Display digits 0:5 0xX5 X 1 0 1

Display digits 0:2 0xX2 X 0 1 0 Display digits 0:6 0xX6 X 1 1 0

Display digits 0:3 0xX3 X 0 1 1 Display digits 0:7 0xX7 X 1 1 1

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