STC89C52 pin map and STC89C52 single-chip pin function description

STC89C52RC is a low-power, high-performance CMOS8 bit microcontroller produced by STC, with a read-only memory that can be programmable with 8K byte system. Let’s take a look at the STC89C52 pin map, and the pin function of the STC89C52 single-chip microcomputer.

STC89C52RC is a low-power, high-performance CMOS8 bit microcontroller produced by STC, with a read-only memory that can be programmable with 8K byte system. Let’s take a look at the STC89C52 pin map, and the pin function of the STC89C52 single-chip microcomputer.

stc89c52引脚图.jpg STC89C52 Ping Diagram

STC89C52 Pin Function Description

1. Main power supply Foot VCC and VSS

The power supply Vcc is connected to + 5V, the VSS ground end, i.e., public reference

2. Clock Circuit Pin XTAL1 and XTAL2

The inside of the STC89C52 chip is provided with an inverting amplifier, XTAL1 is an amplifier input; XTAL2 is an output terminal of the amplifier, and is an internal clock generator. Input.

When using a self-shaking, XTAL1 and XTAL2 external quartz crystals, the internal oscillator oscillates in accordance with the crystal resonant frequency, generates a clock signal.

3. Control Signal Pins

(1) RST – reset input. When the oscillator works, the RST pin appears two machine cycles or more high levels will be a single-chip reduction.

(2) ALE / PROG – ALE (address latch allowed) output pulse for latching addresses when accessing external program memory or data memory Bit byte. In general, the ALE is still outputting a fixed pulse signal at 1/6 of the clock oscillation frequency, so it outputs the clock or for timing purposes. It should be noted that a ALE pulse will be skipped whenever accessing external data memories. (Generally not used)

(3) Psen – Program Storage Allow (Psen) Output is a read signal for external program memory, when STC89C52 When the external program memory is induced (or data), each machine cycle is valid twice, i.e., output two pulses, during which time the external data memory is accessed, two PSEN signals will be skipped.

(4) EA / VPP – external access allows for only the CPU only accesses the external program memory (0000h-fffh), and the EA end must remain low. (Ground). It is to be noted that if the dose LB1 is programmed, the EA-side state is latched inside during reset. If the EA end is a high level (connected VCC terminal), the CPU performs instructions of the internal program memory. When the Flash Memory is programmed, the pin plus + 12V programming allows the power VPP, of course, this must be that the device is using a 12V program voltage VPP.

(5) Parallel I / O port P0 ~ P3 end pin

1P0 port (P0.0 ~ P0.7) 8-bit drain switch type two-way I / O port. It can be used as a general purpose I / O port, but a pull resistor must be added.

2P1 port (P1.0 ~ P1.7) The 8-position bidirectional I / O port with the upper tensile resistance is used.

3P2 port (P2.0 ~ P2.7) The 8-position bidirectional I / O port of the upper tensile resistance is used.
4P3 port (P3.0 ~ P3.7) The 8-bit multifunctional two-way I / O port with the upper pull resistance is used.

The above is the STC89C52 pins and the STC89C52 pin function description, I hope to help everyone.

Original article,author:zongmuLi,If reprinted,Please indicate the source:http://madedesign.net/index.php/2020/12/13/stc89c52-pin-map-and-stc89c52-single-chip-pin-function-description/

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