MAX1576 Datasheet, PDF (16/22 Pages) Maxim Integrated Products – 480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera Flash

Table 2. Register Access for Two or More Cascaded Devices
Configuration Register Access
Display Register Access
Criteria*
Total Number of Bytes
Number of Leading
“Don’t Care” Bytes
Total Number of Bytes
Number of Leading
“Don’t Care” Bytes
If 3N is a Multiple of 4
3N
2
3N + 2
2
If 3N – 1 is a Multiple of 4
3N – 1
1
3N + 1
1
If 3N – 2 is a Multiple of 4
3N – 2
0
3N
0
If 3N – 3 is a Multiple of 4
3N – 2
0
3N
0
* N = number of devices that are cascaded. For example, to drive 10 digits, 2 devices are cascaded; therefore, N = 2. To drive 35 digits, seven
devices are cascaded; therefore N = 7.
+5V
CMOS
MCU/MPU
LED DISPLAY
8
5
VDD
Rx
MC14489B
VSS
+5V
R1
R2
NOTE: R1 limits the maximum current to avoid damaging the display and/or the MC14489B
due to overheating. See the Thermal Considerations section. An 1/8 watt resistor
may be used for R1. R2 is a 1 kΩ or 5 kΩ potentiometer (≥ 1/8 watt). R2 may be a
light–sensitive resistor.
Figure 15. Common–Cathode LED Display with Dial–Adjusted Brightness
MC14489B
16
MOTOROLA