NuukiaWorld project:
FBUS & MBUS adapters

7. FBUS indicator LED

7.1 Simple mode indicator for NuukiaWorld dual-mode adapters

The NuukiaWorld dual-mode FBUS/MBUS adapter is fully automatic and so you do not need to worry about the mode it is currently using. But it is very simple to add an indicator LED on the adapter to show the active mode.

The most important reason for installing the LED may be that a flashing light makes the adapter more interesting-looking. Three additional components are required, and they are connected in series as shown in figure 6.1 (the order of the components is free, but the directions are important).

Figure 7.1 FBUS mode indicator LED for NuukiaWorld's dual-mode adapter.

Table 7.1 Additional required components for the indicator.



1 1N4148 Any diode for at least 20 mA
1 2 kohm  
1 LED  

Note: Part substitutes marked "Equivalent*" may be used in the circuit without any problems.

Please note that the anodes of the diode and the LED and really connected to the GND side, the LED lights when the RTS is inactive (that is, at a negative voltage level). This ensures that the LED does not affect the operation of the adapter.

The LED lights when the adapter is in the FBUS mode. When the adapter switches to MBUS mode, the LED will go off. The LED lights also when the adapter is idle if the computer is powered. That is correct even if no software is running in any mode.

CAUTION: If the power supplying capacity of your serial port is too low, the LED option disturbs the FBUS mode. If you have problems with FBUS, try to increase the value of the 2 kohm resistor or remove the LED circuit.

7.2 Adding the LED to the dual-mode adapter

The LED has been added to the circuit board layout shown in figure 6.2. Most of this layout is same as in the dual-mode adapter without the LED.

Figure 7.2 Circuit board layout of dual-mode adapter with FBUS indicator for copper-striped board (component side).

7.3 Adding the LED to the super miniature dual-mode adapter

To add the indicator led to the super miniature adapter layout shown in figure 6.2 you must make a two-sided circuit board for the adapter. The layout for the other side is shown in figure 7.3.

Note that the order of the components is different than in figure 7.1, but directions are the same. Use a normal 3 mm LED, a 2 kohm resistor of size 1206, and a minimelf diode.

The LED is installed on the same side as the MAX3221 chip and must be soldered on the both sides of the board. The anode is soldered to the net connected to the pin 1 of the MAX3221. The diode is mounted onto the footprints nearest to the DB9 connector. The cathode of the diode must be connected to the pin 7 (RTS) of the connector; the resistor in installed between the LED and diode.

Figure 7.3 The other side for the super miniature dual mode adapter board for installing the FBUS indicator. To print this layout in scale, use an image processing application and ensure that the printing will happen exactly at 300 pixels per inch. The layout shown is a mirror image; the texts must be readable on the board. (Download Postscript file.)

- © Copyright 1999, 2000 Panu M Tuominen. All rights reserved. Republishing this document partially or completely is forbidden. Internet hyperlinks to the main page are allowed and such linking is encouraged. You are doing everything at your own risk. See the WARNING! in the general information page.

For example, Nokia 5110 and Nokia 6110 are 5100/6100 series phones. The tests have been done with Nokia Data Suite 2.0, Nokia Logo Express, LogoManager demo version, and a Nokia 6110.

21.5.2001 - nuukiaworld@gmail.com
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