Sim Card Supply Voltage Generation; Keypad - Motorola W208 Manual

W208 Level 3 Circuit Description

9.1 SIM Card Supply Voltage Generation

To accommodate the 1.8V or 2.9V SIM cards, the
regulator that delivers supply voltage Pin A3 to the SIM module.
The LDO voltage regulator is configured to generate the 1.8V or 2.9V
A3) supply. The VRSIM

10 Keypad

The keyboard is connected to the chip using:
ROW0-ROW4 (KBR[0:5]) input pins for row lines
COL0-COL4 (KBC[0:5]) output pins for column lines
If a key button of the keyboard matrix is pressed, the corresponding row and column lines
are shorted.
To allow key press detection, all input pins (KBR[0:5]) are pulled up to VCC and all output
pins (KBC[0:5]) are driving a low level. Any action on a button will generate an interrupt
to the microcontroller which will, as answer, scan the column lines with the sequence
describe below.
This sequence is written to allow detection of simultaneous press actions on several key
buttons.
From Triton-Lite
SIMIO
SIMCK
SIMRST
Locost-Plus
Figure 15: SIM interface
J701 Pin 4 and 5 terminals are decoupled by a capacitor (C709).
Figure 16: Keyboard scanning sequence
Service Engineering & Optimization
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VRSIM
VCC
SIM-IO
I/O
SIM-CLK
CLK
SIM-RST
RST
GND
SIM Connecter
Triton-Lite includes an LDO voltage
(VRSIM U103 Pin