Kenwood NXR-700 Service Manual

Also see for NEXEDGE NXR-700: Brochure Instruction manual Service manual Instruction manual Instruction manual

Contents

NXR-70079■ Start-up of each Control Block• Main MPU BlockComponent elements:· Main MPU: IC703· Flash memory: IC702· SDRAM: IC704 and IC707· LAN IC: IC719· RTC: IC701Overview of Start-up Operation:When MPU reset line logic switches as high, the MPUstarts reading the program from the flash memory and ex-pands the program to SDRAM. Linux OS begins operationon the SDRAM after main MPU transfers the program. MainMPU works usage of Linux OS codes. The other higher-level applications software to the Linux OS will also beexpanded in SDRAM. On starting up, main MPU verify thestatus of the registers in LAN IC except SDRAM which ispurpose of backup data even if abnormal symptom detectsin either LAN IC or SDRAM, the start-up process is not af-fected by this error; main MPU behaves operation as if itworks properly. To express another word, either Flash mem-ory or SDRAM has defective, a circuit behaves as if mainMPU happens malfunction. After executing all initializationroutines, the Main MPU verifies the operational status ofeach MPU then transmits/ receives the operation transfercommand set to from the Modem control MPU (IC325) andthe RF control MPU (IC34) using 115.2kbps UART commu-nications.• RF Control MPU BlockComponent elements:· RF control MPU: IC34· Flash memory: IC17· DSP: IC37Overview of Start-up Operation:When the RF control MPU (IC34) reset line logic switchesas high, this MPU reads the boot program from the internalROM of MPU and then initializes the peripheral devices. Af-ter this boot process completes, the MPU starts working withthe programs (application programs) stored in flash memory(IC17) to process the preprogrammed tasks. During the pro-cess, the MPU transfers the program to the DSP IC (IC37).It also verifi es the operating status of DSP at certain interval.After a series of processes completes, the RF controlMPU verifies the operational status and then transmits andreceives the operation transfer command set to/from MainMPU (IC703) using 115200bps UART communications.• Modem Control MPU BlockComponent elements:· Modem control MPU: IC325· Flash memory: IC314· RX DSP: IC323· TX Vocoder DSP: IC324Overview of Start-up OperationWhen the Modem control MPU (IC325) reset line logicswitches as high, the MPU reads the boot program from theinternal ROM of MPU and then initializes the peripheral de-vices. After this boot-up process completes, the MPU startsworking with the programs (application programs) stored inflash memory (IC314) to process the preprogrammed tasks.During the process, the MPU transfers the program to theRX DSP IC (IC323) and TX Vocoder DSP IC (IC324). It alsoconfirms the operating status of these DSP ICs. After a se-ries of processes completes, the Modem control MPU con-fi rms the operational status and then transmits and receivesthe operation transfer command set to/from Main MPU(IC703) using 115200 bps UART communications.• Possible Symptoms if the Block (mainly BGA IC)MalfunctionsRef. No. Element ofBlock Presumption SymptomsIC703 Main MPU• Since the boot program cannot be executedat all, the LEDs do not light or fl ash.• The operations that should be executed byIC703 are not processed.• Runaway of IC703.IC17FlashMemoryon RFcontrolMPU block• Migrated to the programming mode (Write).(“PG” appears on the 17-segment LED dis-play.)• The operations that should be executed byIC34 are not processed.• Runaway of IC34.IC314FlashMemoryon Modemcontrolblock• Migrated to the programming mode (Write).(“PG” appears on the 17-segment LED dis-play.)• The operations that should be executed byIC325 are not processed.• Runaway of IC325.IC323 RX DSP• While the boot program is executed, theoperation stops (the status LED is fl ashing).• The operations that should be executed byIC323 are not processed.• Runaway of IC323.IC324TXVocoderDSP• While the boot program is executed, theoperation stops (the status LED is fl ashing).• The operations that should be executed byIC324 are not processed.• Runaway of IC324.TROUBLE SHOOTING