AS1115 austriamicrosystems AG, AS1115 Datasheet - Page 20

• Manufacturer Part Number: AS1115
• Description: Interfaced LED Driver
• Manufacturer: austriamicrosystems AG

AS1115
Datasheet - Ty p i c a l A p p l i c a t i o n
8x8 Dot Matrix Mode
The application example in
The LED columns have common cathodes and are connected to the DIG0:7 outputs. The rows are connected to the
segment drivers. Each of the 64 LEDs can be addressed separately. The columns are selected via the digits as listed
in
The Decode Enable Register
LEDs in a column can be addressed as described in
bit D7 corresponds to segment DP.
Figure 26. Application Example as LED Dot Matrix Driver
Keyscan
The key readback of the AS1115 can be used either for push buttons as well as switches. If only a single key is
pressed (shorted) at a time no additional diodes are required. If a detection of multiple simultaneous keystrokes is
required diodes within the keypath, as shown in
would result in ambiguous results. Since KEYA and KEYB have independent inputs only keys on the same path are
affected.
Figure 27. Keyscan Configuration
Supply Bypassing and Wiring
In order to achieve optimal performance the AS1115 should be placed very close to the LED display to minimize effects
of electromagnetic interference and wiring inductance.
Furthermore, it is recommended to connect a 10µF and a 0.1µF ceramic capacitor between pins V
avoid power supply ripple
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Table 6 on page
2.7 to 5V
µP
V
DD
KEYA
KEYB
IRQ
9.53kΩ
SDA
SCL
IRQ
12.
(see Figure
Figure 26
SDA
SCL
I
IRQ
SET
SEGA
(see page
AS1115
shows the AS1115 in the 8x8 LED dot matrix mode.
26).
SEGB
13) must be set to ‘00000000’ as described in
GND
Figure
SEGC
Table 11 on page
SEG A to G
SEP DP
DIG0 to
DIG7
Revision 1.03
Diodes are optional and only required if multiple keystrokes must be
detected simultaneously.
If I²C Self-Adressing is used these two keys cannot be used for read-
back and must be either hard wired opened or shorted.
A short writes a logical “1” whereas an open writes a logical “0” as
address bit.
27, are required. Pressing multiple keys without the diodes
Diode Arrangement
SEGD
15, where bit D0 corresponds to segment G and
SEG E
SEGF
Table 8 on page
SEGG
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DD
SEGDP
and GND to
13. Single
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