www.austriamicrosystems.com/LED-Driver-ICs/AS1115

Revision 1.08

16 - 25

AS1115

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

Display-Test Mode

The AS1115 can detect open or shorted LEDs. Readout of either open LEDs or short LEDs is possible, as well as a OR relation of open and

short.

Note:

All settings of the digit- and control-registers are maintained.

LED Diagnostic Registers

These eight registers contain the result of the LED open/short test for the individual LED of each digit.

Note:

If one or more short occures in the LED array, detection of individual LED fault could become ambiguous.

Intensity Control Register (0x0A)

The brightness of the display can be controlled by digital means using the Intensity Control Registers and by analog means using RSET (see

Selecting RSET Resistor Value and Using External Drivers on page 19

). The intensity can be controlled globally for all digits, or

for each digit individually. The global intensity command will write intensity data to all four individual brightness registers, while the individual

intensity command will only write to the associated individual intensity register.

Table 14. Testmode Register Summary

D7

D6

D5

D4

D3

D2

D1

D0

X

RSET_short

RSET_open

LED_global

LED_test

LED_open

LED_short

DISP_test

Table 15. Testmode Register Bit Description (Address (HEX) = 0x0F))

Addr: 0x0F

Address

Bit

Bit Name

Default

Access

D7:D0

D0

DISP_test

0

W

Optical display test. (Testmode for external visual test.)

0: Normal operation; 1: Run display test (All digits are tested independently

from scan limit & shutdown register.)

D1

LED_short

0

W

Starts a test for shorted LEDs. (Can be set together with D2)

0: Normal operation; 1: Activate testmode

D2

LED_open

0

W

Starts a test for open LEDs. (Can be set together with D1)

0: Normal operation; 1: Activate testmode

D3

LED_test

0

R

Indicates an ongoing open/short LED test

0: No ongoing LED test; 1: LED test in progress

D4

LED_global

0

R

Indicates that the last open/short LED test has detected an error

0: No error detected; 1: Error detected

D5

RSET_open

0

R

Checks if external resistor RSET is open

0: RSET correct; 1: RSET is open

D6

RSET_short

0

R

Checks if external resistor RSET is shorted

0: RSET correct; 1: RSET is shorted

D7

0

-

Not used

Table 16. LED Diagnostic Register Address

Register

HEX

Address

Segment

Register

HEX

Address

Segment

Digit

D7

D6

D5

D4

D3

D2

D1

D0

Digit

D7

D6

D5

D4

D3

D2

D1

D0

0x14

DIG0

DP

A

B

C

D

E

F

G

0x18

DIG4

DP

A

B

C

D

E

F

G

0x15

DIG1

0x19

DIG5

0x16

DIG2

0x1A

DIG6

0x17

DIG3

0x1B

DIG7