1, the circuit analog switch can be used for serial ports. Is a cut that supports usb and serial communicationChange the analog switch. Classification Due to the use of MOS tube breaking performance, analog switching circuit can achieve a high turn-off impedance, generally more than megohm switching impedance, and very low on-impedance, generally several ohm levels, so it can be a good realization of signal link switching and disconnection isolation.
2, stc89c52 MCU does have a serial port, of course, you can add an analog switch to expand the two serial ports, but the two serial ports are time-sharing work, that is, can not send and receive at the same time.
3, if it is determined not to send and receive at the same time, you can sit through the diodeElectrical isolation of the hardware, and then based on the time period to know which route to the data. It can also be switched using the dual four-way analog switch CD4052.
4, CMOS three sets of two analog switch CD4053BE pin function: 1,16 pin: symbol VDD, pin function is the power supply "". 2,8 pin: symbol Vss, the pin function is the digital signal grounding terminal. Pin 3,7: symbol VEE, the pin function is the analog signal grounding terminal.
5, this analog switch in the channel selection has a maximum of 90ns delay time, you'd better inSet the delay after switching channels. It has a minimum bandwidth of 10MHz, and your bit rate should be adapted to that.
6, is it on the computer? Or is it on a microcontroller? If two serial ports on the computer, of course, can work at the same time, are two independent serial ports. Is the single chip microcomputer, depending on what is the single chip microcomputer, if the two serial ports of the single chip microcomputer are independent, you can work at the same time, such as STC12C5A60S2, STC15F2A60S2, two serial ports can work at the same time. If the two serial ports are implemented by analog switching, they will not work at the same time.
1, CMOS three sets of two-way analog switch CD4053BE pin function: 1.16 pin: VDD symbol, pin function for power "+". 2.8 Pin: symbol Vss, pin function is the digital signal ground end. 3.7 Pin: symbol VEE, pin function is analog signal ground end.
2, CD405Functions of the 3BE pin: Pin 1.16: VDD is the symbol, and the pin function is power "+". 2.8 Pin: symbol Vss, pin function is the digital signal ground end. 3.7 Pin: symbol VEE, pin function is analog signal ground end. 4.6 Pin: INH symbol, pin function is forbidden to end zero, CMOS three sets of two analog switches CD4053BE work, otherwise CMOS three sets of two analog switches CD4053BE prohibited work.
3, pin: VDD is the symbol, the pin function is power "". 8 Pin: Symbol Vss, the function of this pin is to ground the digital signal. 7 pin: symbol VEE, pin function is analog signal ground. 6 pin: INH symbol, the function of the pin is to prohibit the end of zero, CMOS three sets of two analog switches CD4053 work, otherwise CMOS three sets of two analog switches CD4053 work.
4, double four-way analog switch CD4052 Pin function of CD4052 see Figure 3. CD4052 is equivalent to a two-pole four-throw switch, which channel is connected by the input address code AB to determine. Three sets of two-way analog switches CD4053 CDThe pin function of the 4053 is shown in Figure 4. CD4053 contains 3 groups of single-pole double-throw switches, which channel is connected to the 3 groups of switches, determined by the input address code ABC.
5, SN74LS160 is a counter (decimal); CD4053 is an analog switch (three-channel choice one), the function is to select the signal path; The LM324 is an op-amp (four-op-amp) that amplifies the signal voltage.