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AS1100

Datasheet - D e t a i l e d D e s c r i p t i o n

8 Detailed Description

8.1 Serial-Addressing Modes

Programming of the AS1100 is done via 4 wire serial interface. A programming sequence consists of 16-bit packages. The data is shifted into the

internal 16 Bit register with the rising edge of the CLK signal. With the rising edge of the LOAD signal the data is latched into a digital or control

register depending on the address. The LOAD signal must go to high after the 16th rising clock edge. The LOAD signal can also come later but

just before the next rising edge of CLK, otherwise data would be lost. The content of the internal shift register is applied 16.5 clock cycles later to

the DOUT pin. The data is clocked out at the falling edge of CLK. The Bits of the 16Bit-programming package are described in Table 5. The first

4 Bits D15-D12 are don’t care, D11-D8 contain the address and D7-D0 contain the data. The first bit is D15, the most significant bit (MSB). The

exact timing is given in Figure 5.

Figure 5. Timing Diagram

8.2 Digit and Control Registers

The AS1100 incorporates 15 registers, which are listed in Table 5. The digit and control registers are selected via the 4Bit address word. The 8

digit registers are realized with a 64bit memory. Each digit can be controlled directly without rewriting the whole contents. The control registers

consist of decode mode, display intensity, number of scanned digits, shutdown, display test, and reset/external clock register.

8.3 Shutdown Mode

The AS1100 features a shutdown mode, where it consumes only 20 A current. The shutdown mode is entered via a write to register 0Ch. Then

all segment current sources are pulled to ground and all digit drivers are connected to VDD, so that nothing is displayed. All internal digit

registers keep the programmed values. The shutdown mode can either be used for power saving or for generating a flashing display by

repeatedly entering and leaving the shutdown mode. The AS1100 needs typically 250 s to exit the shutdown mode. During shutdown the

AS1100 is fully programmable. Only the display test function overrides the shutdown mode.

8.4 Initial Power-Up

After powering up the system all register are reset, so that the display is blank. The AS1100 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.

Table 4. Serial Data Format (16bits)

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

X

X

X

X

Address

MSB

Data

LSB

D0

D1

D15

D14

DOUT

DIN

CLK

LOAD

tCSW

tCL

tCH

tCP

tCS

tLDCK

tDO

tDS

tDH