Kenwood TK-3148 Service Manual page 16

TK-3148
6. Control Circuit
The control circuit consists of MCU (IC309) and its periph-
eral circuits. It controls the TX-RX unit and transfers data to
and from the display unit. IC309 mainly performs the follow-
ing;
1) Switching between transmission and reception by PTT
signal input.
2) Reading system, group, frequency, and program data
from the memory circuit.
3) Sending frequency program data to the PLL.
4) Controlling squelch on/off by the DC voltage from the
squelch circuit.
5) Controlling the audio mute circuit by decode data input.
6) Transmitting tone and encode data.
6-1. Memory circuit
Memory circuit consists of the MCU (IC309) and a fl ash
memory (IC308), a fl ash memory has a capacity of 4M bits
that contains the transceiver control program for the MCU
and data such as transceiver channels and operating fea-
tures.
This program can be easily written from an external de-
vices. Data. such as operating status, are programmed into
the EEPROM (IC310).
• Flash Memory
Note: The flash memory stores the data containing the
FPU (KPG-74D CPS) program, Security Number (MPT Serial
Number) and firmware program (User mode, Test mode,
Tuning mode, etc.). This data must be reinstalled when re-
placing the fl ash memory.
• EEPROM
Note: The EEPROM stores tuning data (Deviation, Squelch,
etc.). Realign the transceiver after replacing the EEPROM.
6-2. Low battery warning
The battery voltage is monitored by the MCU (IC309).
When the battery voltage falls below the voltage set by the
Low Battery Warning adjustment, the red LED flashes to
notify the operator that it is time to replace the battery. If
the battery voltage falls even more (approx. 6.1V), a beep
sounds and transmission is stopped.
Low battery warning
The red LED fl ashes during
transmission
The red LED fl ashes and
continuous beep sounds
while PTT pressed
16
CIRCUIT DESCRIPTION /
IC308
FLASH
Fig. 9 Memory circuit / 图 9 存储器电路
Battery condition
The battery voltage is low but the
transceiver is still usable.
The battery voltage is low and the
transceiver is not usable to make
calls.
电路说明
6．控制电路
控 制 电 路 由 M C U ( I C309) 和 其 外 围 电 路 组 成。M C U 控 制
TX-RX 单元和发送到显示单元的数据以及从显示单元发送的数
据。IC309 主要执行下述功能 :
1) 通过 PTT 信号输出在发射和接收之间转换。
2) 从存储器电路读取系统，组，频率和编程数据。
3) 向 PLL 发送频率编程数据。
4) 通过来自于静噪电路的直流电压控制静噪的开启 / 关闭。
5) 通过解码数据输入控制音频静音电路。
6) 发送音频和编码数据。
6-1. 存储器电路
记忆电路由 MCU(IC309) 和一块闪存 (IC308) 组成。闪存容
量 4MB，载有 MCU 所需的收发机控制程序以及收发机信道、功
能设置等数据。
可以方便地使用外部设备写这个程序。工作状态等数据编
写在 EEPROM(IC310) 中。
• 闪存
注释 : 闪存保存的数据包括 FPU(KPG-74D CPS) 程序，安全码
(MPT 序列号 ) 和固件编程 ( 用户模式， 测试模式， 调谐模式等 )。
当更换闪存时，必须重新安装数据。
• EEPROM
注释 : EEPROM 保存调谐数据 ( 频偏，静噪 )。更换 EEPROM 后
重新调校对讲机。
IC309 IC310
EEPROM
MCU
6-2. 电池低压告警
通过 MCU(IC309) 监视电池电压。当电池的电压低于通过电
池低压告警调整设定的电压时，红色指示灯闪烁以提示操作
者更换电池。如果电池的电压继续降低 ( 大约 6.1V)，则发出
beep 音并停止发送。
电池低压告警
发射过程中红色指示灯闪烁。
当按下 PTT 键时红色指示灯闪烁
并且对讲机发出连续 beep 音。
电池状态
电池电压降低但仍可使用对
讲机。
电池电压降低不能使用对讲
机发出呼叫。