Nokia NSE–3 SERIES Service Manual

Contents

Nokia NSE–3 SERIES Service Manual Manual pdf 49 page image

PAMSTechnical DocumentationNSE–3System ModulePage 3 – 43Original 11/97MemoriesThe MCU program code resides in an external flash program memory,which size is 8 Mbits (512kx16bit). The MCU work (data) memory size is512kbits (64kx8bit). A serial EEPROM is used for storing the system andtuning parameters, user settings and selections, a scratch pad and ashort code memory. The EEPROM size is 64kbits (8kx8bit).The BusController (BUSC) section in the MAD decodes the chip selectsignals for the external memory devices and the system logic. BUSC con-trols internal and external bus drivers and multiplexers connected to theMCU data bus. The MCU address space is divided into access areas withseparate chip select signals. BUSC supports a programmable number ofwait states for each memory range.Program MemoryThe MCU program code resides in the program memory. The programmemory size is 8 Mbits (512kx16bit).The flash memory has a power down pin that should be kept low, duringthe power up phase of the flash to ensure that the device is powered upin the correct state, read only. The power down pin is utilized in the sys-tem sleep mode by connecting the ExtSysResetX to the flash power downpin to minimize the flash power consumption during the sleep.SRAM MemoryThe work memory is a static ram of size 512k (64kx8) in a shrink TSOP32package. The work memory is supplied from the common baseband VBBvoltage and the memory contents are lost when the baseband voltage isswitched off. All retainable data should be stored into the EEPROM (orflash) when the phone is powered down.EEPROM MemoryAn EEPROM is used for a nonvolatile data memory to store the tuningparameters and phone setup information. The short code memory forstoring user defined information is also implemented in the EEPROM.The EEPROM size is 8kbytes. The memory is accessed through a serialbus and the default package is SO8.