AS1105WL austriamicrosystems, AS1105WL Datasheet - Page 7

• Manufacturer Part Number: AS1105WL
• Description: IC LED 4-DIGIT DRIVER 20-SOIC
• Manufacturer: austriamicrosystems

Specifications of AS1105WL

• Display Type: LED
• Configuration: 7 Segment + DP
• Interface: Serial
• Digits Or Characters: 4 Digits
• Current - Supply: 330mA
• Voltage - Supply: 4 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS1105
Data Sheet - D e t a i l e d D e s c r i p t i o n
Initial Power-Up
After powering up the system, all register are reset, so that the display is blank. The AS1105 starts the shutdown mode.
All registers should be programmed for normal operation. The default settings enable only scan of one digit, the
internal decoder is disabled, data register and intensity register are set to the minimum value.
Decode-Mode Register
In the AS1105, a BCD decoder is included. Every digit can be selected via register 09h to be decoded. The BCD code
consists of the numbers 0-9, E,H, L,P and -. In register 09h, a logic high enables the decoder for the appropriate digit.
In case that the decoder is bypassed (logic low), the data Bits D7-D0 correspond to the segment lines of the AS1105.
In
affected by the settings of the decoder. Logic high means that the decimal point is displayed. In
Code B decoder is shown. In
display is shown
Intensity Control and Interdigit Blanking
Brightness of the display can be controlled in an analog way by changing the external resistor (R
which flows between V
I
brightness of the display can also be controlled digitally via register 0Ah. The brightness can be programmed in 16
steps and is shown in
Scan-Limit Register
The scan limit register 0Bh selects the number of digits displayed. When all 4 digits are displayed the update frequency
is typically 800Hz. If the number of digits displayed is reduced, the update frequency is reduced as well. The frequency
can be calculated using 8fOSC/N, where N is the number of digits. Since the number of displayed digits influences the
brightness, the resistor R
fewer than 4 digits are used. To avoid differences in brightness the scan limit register should not be used to blank
portions of the display (leading zeros).
Table 5. Register Address Map
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SET
Reset and ext. Clock
Table 7
current. The minimum value of R
Decode Mode
Display Test
Scan Limit
Shutdown
Register
Not used
Intensity
No-Op
Digit 0
Digit 1
Digit 2
Digit 3
some possible settings for register 09h are shown. Bit D7, which corresponds to the decimal point, is not
(see Figure
Table
DD
SET
and I
10. An internal pulse width modulator controls the intensity of the display.
6).
should be adjusted accordingly.
Table 10
D15-D12
SET
X
X
X
X
X
X
X
X
X
X
X
X
, defines the current that flows through the LEDs. The LED current is 100 times the
SET
the correspondence of the register to the appropriate segments of a 7 segment
should be 9.53kΩ, which corresponds to 40mA segment current. The
D11
Register
0
0
0
0
0
1
1
1
1
1
1
1
Revision 1.34
D10
0
0
0
0
1
0
0
0
1
1
1
1
Table 12
D9
0
0
1
1
0
0
1
1
0
0
1
1
shows the maximum allowed current, when
D8
0
1
0
1
0
1
0
1
0
1
0
1
Hex Code
Table 8
0xXA
0xXB
0xXC
0xXD
0xXE
0xX0
0xX1
0xX2
0xX3
0xX4
0xX9
0xXF
SET
). The current,
the font of the
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