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AS1109

Data Sheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

Error Detection

The AS1109 features two types of error detection. The error detection can be used on-the-fly, for active LEDs, without

any delay, or by entering into low-current diagnosis mode.

Error Detection On-The-Fly

Error detection on-the-fly will output the status of active LEDs during operation. Without choosing an error mode this

will output the temperature flag at every input/output cycle. Triggering one clock pulse for open or two clock pulses for

short detection during error detection mode outputs the detailed open- or short-error report with the next input/output

cycle (see Figure 20). LEDs that are turned off cannot be tested and their digits at the error output must be ignored.

Figure 20. Normal Operation with Error Detection During Operation – 128 Cascaded AS1109s

Error Detection with Low-Current Diagnosis Mode

This unique feature of the AS1109 uses an internal all 1s test pattern for a flicker free diagnosis of all LEDs. This error

detection mode can be started anytime, and does not require any SDI input (see Figure 21).

Figure 21. Low-Current Diagnosis Mode with Internal All 1s Test Pattern – 128 Cascaded AS1109s

Display

SDI

SDO

CLK

OEN

LD

Current

Data1

Data2

Data3

T/O or S Error Code

Data1

T/O or S Error Code

Data0

T/O or S Error Code

Data2

1024x

1024x

1024x

Clock for Error

Mode 0x/1x/2x

Rising Edge of OEN

Acquisition of Error Status

Falling Edge of LD; Error Register is

copied into Shift Register

≤ 100mA

GEF

GEF

GEF = Global Error Flag

Falling Edge of LD; Error Register is

copied into Shift Register

Clock for Error

Mode 0x/1x/2x

Rising Edge of OEN

Acquisition of Error Status

Data2

Data3

Data4

GEF

1024x

1024x

Data0

Data1

Rising Edge of OEN

Acquisition of Error Status

Falling Edge of LD; Error Register

is copied into Shift Register

GEF

O or S Error Code of

All 1s Test Patern

Temperature Error Code

Load Internal All 1s Test Pattern

≤ 100mA

≤ 100mA

2µs Low-Current Diagnosis Mode

3x Clocks Low-

Current Mode

Clock for Error

Mode 1x/2x

Display

SDI

SDO

CLK

OEN

LD

Current

≤ 0.8mA

GEF = Global Error Flag

Data1

Data2