Service Manual

Data created thus are 4-phase modulated by one pair of Pilot PN code and they are used to create I and Q data.
When received, I and Q data are demodulated into symbols by the demodulator and then, de-interleaved in reverse
to the case of transmission. Then, the errors of data received from Viterbi decoder are detected and corrected. They
are voice decoded at the vocoder in order to output digital voice data.
The MSM3000 has a improved feature not found on the MSM2300. The MSM3000 supports Enhanced Variable
Rate Coder (EVRC) operation in addition to the standard 8k and 13k vocoding rating.
3.3.4 Memory Part
Memory part consisit of Flash Memory,SRAM and EEPROM.
In the Flash Memory part included SRAM of U308 (8M x 2M bits), there are programs used for terminal operation.
The programs can be changed through down loading after the assembling of terminals. On the SRAM(2Mbits), data
generated during the terminal operation are stored temporarily. On EEPROM (128Kbits) which is U307, non-volatile
data such as unique numbers (ESN) of terminals are stored.
3.3.5 Power Supply Part
When the External DC (4.2V) is fed to the five regulators generated +3.0V. The generated voltages are used for
MSM3000, IFT3000,IFR3000, audio codec, and other LOGIC parts. PWR ASIC is operated by the control signal
SLEEP/ from MSM3000 and POWER_EN signal. Q606(DTC114EE) is turned on by ON_SW_SEN
SE/ and then, 'L' is outputted on ON_SW_SENSE/. MSM receives this signal and then, recognizes that the POWER
key has been pressed. During this time, MSM outputs PS_HOLD as 'H' and then, continues to activate D603 in
order to maintain power even if the PWR key is separated.
3.3.6 Logic Part
The Logic part consists of internal CPU of MSM, RAM, ROM and EEPROM. The MSM3000 receives TCXO
(=19.68Mz) from U7 and CHIPX8 clock signals from the IFR3000, and then controls the phone during the CDMA
and the FM mode. The major components are as follows:
CPU : ARM7TDMI core
FLASH MEMORY + SRAM: U308 (LRS13061)
• FLASH ROM : 8Mbits
• STATIC RAM : 2Mbits
EEPROM : U307 (X84129S161-2.5)
• 128Kbits EEPROM
CPU
ARM7TDMI CMOS type 16-bit microprocessor is used and CPU controls all the circuitry. For the CPU clock,
27MHz is used.
FLASH ROM and SRAM