Interface circuit for reading and writing IC card by CPU I/O port
A technology of interface circuit and power supply control circuit, which is applied in the field of interface circuit and can solve the problems of increasing hardware cost and so on
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[0018] Below in conjunction with accompanying drawing of description, the interface circuit that the present invention uses the I / O port of CPU to read and write IC card is described further.
[0019] figure 1 It is the circuit block diagram of the interface circuit of reading and writing IC card using the I / O port of CPU in the present invention, wherein GPC3, GPG4, GPF7, GPG6, GPF4, GPF3 are respectively any 6 data references of any group of I / O ports of CPU GPC3 and GPG4 are connected to the VCC pin of the IC card through the power supply control circuit, GPC3 is used to control the voltage shutdown of the IC card, GPG4 is used for the short-circuit protection of the IC card power supply (preventing the wrong insertion of iron sheets); GPF7 is connected to the IC card The RST pin of RST provides a reset signal, GPG6 is connected to the SWI pin of the IC card (IC card detection), and GPF4 and GPF3 are connected to the I / O of the IC card through the I / O signal processing circ...
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