AS1112
Datasheet ꢀ Detailed Description
Figure 14. Greyscale Data Input Timing Diagram
Dot Correction Mode
Data Input Cycle
1st Greyscale Mode
Data Input Cycle After Dot Correction Input
Following Greyscale Mode
Data Input Cycle
MODE
tH3
tSU3
LD
tWH2
GSn
MSB
DCn-1
LSB
GSn
LSB
GSn+1
MSB
GSn+1
LSB
SDI
tH2
tSU1
tSU2
tH0
1
tPD0
CLK
96
192
1
192
SIDn
MSB-1
DCn-1
MSB-1
DCn-1
MSB
SIDn
MSB-2
SIDn
LSB
SIDn
MSB
SIDn
MSB
SDO
x
x
x
Status Information Data (SID)
The AS1112 contains an integrated status information register, which can be accessed in greyscale mode (MODE = GND). Once the LD signal
latches the data into the greyscale register, the input shift register data is replaced with status information data (see Figure 15).
Open, shorted LED, temperature warning and overtemperature flags as well as the dotꢀcorrection registers can be read out at pin SDO. The staꢀ
tus information data packet is 192 bits wide. Bits 191:176 and 31:16 contain the open LED detection status of each channel (either 191:176 or
31:16 can be used for readout). Bit 175 contains the thermal error flag status. Bit 174 contains the temperature warning flag. Bits 167:72 contain
the data of the dotꢀcorrection register. Bit 15:0 contains the LED shorted flags. The remaining bits are reserved. The complete status information
data packet is shown in Figure 15.
Figure 15. Status Information Data Packet Format
MSB
191
LSB
0:15
176
175
174
168
X
167
72
71
X
16:31
LOD
...
...
...
LOD15
...
LOD0
TEF
TWF
DC15.
DC0.
LSD
Open LED
Detect Data
Overtemperature
Flag
DC Values
Bit #
Description
LED Short Detection, LSD
LED Open Detection (Optional, same as bits 176:191), LOD
Undefined
Bit #
168:173
174
175
176:191
Description
Undefined
Temperature Warning Flag (TWF, 125ºC, typ)
Temperature Error Flag (TEF, 150ºC, typ)
LED Open Detection, LOD
0:15
16:31
32:71
72:167
Dot Correction Readback (16 x 6 Bit)
Greyscale PWM Operation
The falling edge of the OEN signal initiates a greyscale PWM cycle. The first GSCLK pulse after the falling edge of OEN increments the
greyscale counter by one and switches on any OUTn whose greyscale value does not equal zero. Each subsequent rising edge of GSCLK increꢀ
ments the greyscale counter by one.
The AS1112 compares the greyscale value of each OUTn channel with the greyscale counter value. All OUTn whose greyscale values equal the
counter values are switched off. A OEN = 1 signal after 4096 GSCLK pulses resets the greyscale counter to zero and completes a greyscale
PWM cycle (see Figure 16).
www.austriamicrosystems.com/LEDꢀDriverꢀICs/AS1112
Revision 1.13
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