mc14489b Freescale Semiconductor, Inc, mc14489b Datasheet - Page 16

• Manufacturer Part Number: mc14489b
• Description: Multy-character Led Display/lamp Driver
• Manufacturer: Freescale Semiconductor, Inc

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