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1.功能与特点该块采用22个引脚,为双列塑料封装,由振荡器定时发生器、键扫描信号输入/输出编码(包括:引导码、用户码、用户反码、功能码、功能反码)、指令译码、编码调制器及遥控信号输出缓冲器等组成。应用电路如图1所示。从图1中可以看出,(20)、(21)脚外接一只陶瓷晶振(KBR455B),由BU5777F内部的振荡电路和外接晶振元件组成一个完整的发射振荡器,其振荡频率为455kHz。由振荡获得的455kHz振荡信号经12分频后,产生供遥控信号调制用的38kHz载波信号;经256分频,形成1.78kHz
1. Features and Features The block uses 22 pins, double plastic package, the oscillator timing generator, key scan signal input / output coding (including: boot code, user code, user code, function code, function Anti-code), instruction decoding, encoding modulator and remote control signal output buffer and other components. Application circuit shown in Figure 1. It can be seen from Fig. 1 that a ceramic oscillator (KBR455B) is externally connected to pins (20) and (21), and a complete transmitting oscillator is formed by the internal oscillation circuit of BU5777F and an external crystal oscillator, and the oscillation frequency is 455 kHz. The 455 kHz oscillation signal obtained from the oscillation is divided by 12 to produce a 38 kHz carrier signal for remote signal modulation; divided by 256 to form a 1.78 kHz