Kenwood NX-820 Service Manual

Also see for NEXEDGE NX-820: Instruction manual Technical details Instruction manual Instruction manual Quick start guide

Contents

NX-82024CIRCUIT DESCRIPTION / 电路说明6. Control CircuitThe control circuit consists of the ASIC (IC507) and itsperipheral circuits. IC507 mainly performs the following:1) Switching between transmission and reception via thePTT signal input.2) Reading system, zone, frequency, and program data fromthe memory circuit.3) Sending frequency program data to the PLL.4) Controlling the squelch on/off using the DC voltage fromthe squelch circuit.5) Controlling the audio mute circuit using the decode datainput.6-1. ASICThe ASIC (IC507) is a 32bit RISC processor, equippedwith a peripheral function and ADC/DAC.This ASIC operates at 18.432MHz clock and 3.3V/1.5VDC. It controls the flash memory, SRAM, DSP, the receivecircuit, the transmitter circuit, the control circuit, and the dis-play circuit and transfers data to or from an external device.6-2. Memory CircuitThe memory circuit consists of the ASIC (IC507), theSRAM (IC503) and the flash memory (IC501). The flashmemory has a capacity of 32Mbit which contains the trans-ceiver control program for the ASIC and stores the data. Italso stores the data for the transceiver channels and operat-ing parameters that are written by the FPU. This programcan be easily written from external devices. The SRAM hasa capacity of 1Mbit which contains the work area and dataarea.■ Flash memoryNote: The flash memory stores the data that is writtenby the FPU (KPG-141D(C)), tuning data (Deviation,Squelch, etc.) and firmware program (User mode, Testmode, Tuning mode, etc.).■ SRAM (static memory)Note: The SRAM has a temporary data area and work area.6-3. Display UnitThe display unit is composed of the LCD driver IC (IC1),the LCD & Key backlight, etc.The LCD is controlled using the 4 serial lines (LCDDI,LCDCE, LCDCL, LCDDO) from the ASIC (IC507).6-4. Key Detection CircuitThe keys are detected using an LCD driver IC (IC1). If apressed key is detected by IC1, the information is passed toIC507 through the serial line.6. 控制电路控制电路由 ASIC (IC507) 和外围电路组成。IC507 主要执行以下功能：1) 由输入的 PTT 信号切换发射和接收。2) 从存储电路读取系统、区域、频率和编程数据。3) 将频率数据发送到 PLL。4) 由静噪电路的 DC 电压控制静噪的开 / 关。5) 由输入的解码数据控制音频静音电路。6-1. ASICASIC (IC507) 是 32 位 RISC 处理器，具备外围功能和ADC/DAC。该 ASIC 以 18.432MHz 时钟和 3.3V/1.5V DC 运行。用以控制闪存、SRAM、DSP、接收电路、发射电路、控制电路以及显示电路，并与外部设备双向传输数据。6-2. 存储电路存储电路由 ASIC (IC507)、SRAM (IC503) 和闪存 (IC501)组成。闪存具有 32M 位的容量，包含 ASIC 的车载对讲机控制程序并储存数据。同时还保存车载对讲机信道的数据及 FPU写入的运行参数。可以轻松通过外部设备写入此程序。SRAM具有 1M 位的容量，包含工作区和数据区。■ 闪存注意：闪存可储存 FPU (KPG-141D(C)) 写入的数据、调谐数据 ( 频偏、静噪等 ) 以及固件程序 ( 用户模式、测试模式、调谐模式等 )。■ SRAM ( 静态存储器 )注意： SRAM 设有临时数据区和工作区。6-3. 显示单元显示单元由 LCD 驱动 IC (IC1)、以及 LCD 和按键背光等部分组成。LCD 通过 ASIC (IC507) 的 4 条串行控制线 (LCDDI、LCDCE、LCDCL、LCDDO) 进行控制。6-4. 按键检测电路使用 LCD 驱动 IC (IC1) 检测按键。如果 IC1 检测到已有按键按下，则会通过串行线路通知 IC507。