AS1130-BTST datasheet(17/67 Pages) AMSOSRAM

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AS1130 − Detailed Description

Cross-Plexing Theorem

The cross-plexing theorem is using the fact that a LED has a

forward and backward direction. A LED will only glow if there

is a current flowing in forward direction. A parallel LED in

backward direction will block the current flow. This effect is

used in a cross-plexed matrix of LEDs.

Each CSx pin (CS0 to CS11) can be switched to VDD via the

internal current source (“high”), to GND (“low”) or not

connected (“highZ”).

The mode of operation which is controlled by an internal state

machine looks like following. CS0 is switched to GND and all

other CSx pins (CS1 to CS11) are controlled according to the

settings in the On/Off Frame and Blink & PWM registers (see

Figure 31).

Than CS1 is switched to GND and all other CSx pins (CS0 and

CS2 to CS11) are controlled according to the settings in the

On/Off Frame and Blink & PWM registers.

In this manner all LEDs in the matrix are scanned and turned

on/off depending on the register settings.

I²C Interface

The AS1130 supports the I²C serial bus and data transmission

protocol in fast mode at 1MHz. The AS1130 operates as a slave

on the I²C bus. The bus must be controlled by a master device

that generates the serial clock (SCLK), controls the bus access,

and generates the START and STOP conditions. Connections to

the bus are made via the open-drain I/O pins SCLK and SDA.

Figure 23:

I²C Interface Initialization

Detailed Description

AD2

AD1 AD0 R/W

D15 D14 D13 D12 D11 D10 D9

AD2, AD1 and AD0 are defined by the pin ADDR, see I²C Device Address Byte.

SCLK

SDA

AS1130-BTST Datasheet(PDF) 17 Page - ams-OSRAM AG