User Guide

RM-31

Nokia Customer Care 7 - System Module

30 COMPANY CONFIDENTIAL Issue 1 03/2005

■ Keypad

The RM-31 keys are connected to the UPP via the KEYB(10:0) bus. The keypad consists of a

5x4 matrix of 5 rows, ROW0 – ROW4, and 4 columns, COL1 – COL4.

Additionally, there are 3 lines that are directly connected to the UPP IO and can be detected

independently. COL5 is connected to GENIO0.

Test possibility

Phoenix Keyboard Test

For troubleshooting, see Keypad faults in Baseband Troubleshooting Instructions.

Figure 10:RM-31 keypad

■ Illumination

In RM-31, white LED’s are used for the LCD backlight and keypad lighting. Three LED’s are

used for the LCD lighting and two LED’s for the keyboard. A step up DC-DC converter is used

as a LED driver that is configured as a constant current source.