NSW-5
System Module UT5U
PAMS Technical Documentation
Page 24
Issue 1 10/00
Nokia Mobile Phones Ltd.
Circuit Description of Submodules
CTRLU
CTRLU comprises MAD ASIC (MCU, DSP, System Logic) and Memories.
The soldering connections of the IC are unaccessible for probing, only
test points can be used. Therefore no pin list is published.
The environment consists of two memory circuits (FLASH,SRAM), a
22–bit address bus and a 16–bit data bus. Besides there are
ROM1SELX, ROM2SELX and RAMSELX signals for chip selection.
MCU main features
– System control
– Cellular Software (CS)
Cellular Software takes care of communication with switching office,
as well call build–up, maintenance and termination.
– Communication control
M2BUS is used to communicate to external devices. This interface is
also used for service and maintenance purposes.
– User Interface (UI)
PWR–key, keyboard, LCD, backlight, mic, ear and alert (buzzer, vibra,
led) control.
Serial interface from MAD to LCD (common for CCONT).
– Authentication
Authentication is used to prevent fraud usage of cellular phones.
– RF monitoring
RF temperature monitoring by VCXOTEMP, ADC in CCONT.
Received signal strength monitoring by RSSI, ADC in CCONT.
False transmission detection by TXF signal, digital IO–pin.
– Power up/down and Watchdog control
When power key is pressed, initial reset (PURX) has happened and de-
fault regulators have powered up in CCONT, MCU and DSP take care of
the rest of power up procedures (LCD, COBBA, RF).
MCU must regularly reset Watchdog counter in CCONT, otherwise
the power will be switched off.
– accessory monitoring
Accessory detection by EAD (XMIC/HEADSETINT), AD–converter in
CCONT.
Connection (FBUS) for data transfer.