X76F 100 is 128×8-bit secure serial flash memory? E2PROM, in which the read password and the write password are 64 bits respectively. Figure 2 shows its Smart card smart? Pin diagram of card package. The chip is packaged on a card, and the card can be read and written by the IC card reader by inserting the card into the card holder, so as to realize the functions of encryption, inquiry, deposit and withdrawal, etc.

There are eight pins in the IC card holder, which are connected with these pins when X76F 100Y is inserted. There are also two fixed ends, one of which is connected with the spring leaf on the card holder, and the two contacts and the reed are equivalent to a normally closed switch. When the card is not inserted, the reed is closed and the P3.2 pin remains low; When inserting the card, the reed is pushed away and the P3.2 pin becomes high. When the microcontroller detects that the P3.2 pin goes high, it passes through P 1.3? Set the RST pin of X76F 100 high to reset it.

2.2? Single chip microcomputer?

The single chip microcomputer adopts GMS97C52 of LG company. It has 8 kilobytes of ROM, 256 kilobytes of RAM and 32 I/O ports. P 1 port is connected with serial devices X25045 and X76F 100, P0 and P2 ports are used for keyboard and display, P3.2 of P3 port is used for detecting whether IC card is inserted, and the remaining seven ports can be used for other function expansion.

2.3? Monitoring circuit?

The monitoring circuit adopts X25045 chip, including watchdog timer, voltage monitoring circuit and E2PROM memory. Its function is to generate a reset signal to GMS 97 c 52； when the power supply is turned on or off; Watchdog monitoring system to prevent system collapse.