Chip STC12C5204AD I/O port configuration STC12C5204AD ries microcontroller its all I/O ports are controlled by the software configuration into 4 kinds of work type 4 types are respectively: quasi two-way mouth (standard the 8051 output mode), push-pull output, only for input (high resistance) or open-drain output functions. Every mouth consists of two control register the relevant position control each pin type of work. STC12C5204AD ries microcontroller to electricity reattachment shall prevail two-way mouth (standard the 8051 output mode) mode: 2V above high level, 0.8 V for low level below.
1. Quasi two-way mouth output configuration
Quasi two-way mouth output type can be ud as output and input function but don't need to reconfigure mouth lines output state. This is becau juncture lines output is 1 drive ability is very weak, allowing external devices will its down. When pins for low, it output driving ability, can absorb the considerable current. Quasi two-way mouth have 3 pull_up transistor adapted to different needs.
In the three and one transistor, pull up transistor called weak on pull ", for 1 and paternal line registers itlf pins for 1 open. This pull_up provides basic drive current make prospective two-way mouth for 1 output. If a pin for 1 and output by external devices to drop down to low, pull up clo and weak "very weak pull_up" maintain open position, in order to put this pin for low, strong to pull the external devices must have enough power to make pin infud current threshold voltage of a voltage to the following.
Article 2 pull_up transistors, called "extremely weak on pull", 1 latch paternal line when open. When pin, the very weak suspended the pull_up source generates very weak and current will pin and high level.
Article 3 pull_up transistor called "powerful pull". Juncture line latches from 0 to 1, the jumping to accelerate must pull up by logic 0 to two-way mouth logic 1 conversion. When this happened, powerful pull open about 2 machine cycle to make pins can quickly pull to the earth high level.
Quasi two-way mouth output shown below.出席英文
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STC12C520 ries microcontroller 3V device, if the ur is in pins plus 5V voltage, there will be a current flow from pins, this has caud additional VDD power consumption. Accordingly, the proposal is not in quasi two-way mouth mode 3V microcontroller pins to exert 5V voltage, such as the u of words, will add current limiting resistor, or using diode do input isolation, or u triode do output gregation.
Quasi two-way mouth with a schmidt trigger input and a interference suppression circuit.
2. The push-pull output configuration
The drop-down push-pull output configuration open-drain output and the structure and the prospective two-way mouth down same structure, but when latches is 1 provides continuous strong pull up. The push-pull model need more commonly ud for driving current situation.贸易商是什么意思
The push-pull pins configuration are shown below.
报价技巧3. Only for input (high resistance) configuration
Input port configuration are shown below.
limInput port with a schmidt trigger input and a interference suppression circuit.
4. Open-drain output configuration
Juncture line latches is 0, the open-drain output clo all pull_up transistors. When, as a logical output, this configuration mode must have externally pull, usually by resistance receiving V D D outside. This style of drop-down and quasi two-way mouth the same. The jammer line configuration are shown below.
Open-drain port with a schmidt trigger input and a interference suppression circuit.
A typical transistor control circuit
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If u weak pull_up control, suggestion plus pull-up resistors R1 (3.3 K ~ 10K), if not add pull-up resistors R 1 (3.3 K ~ 10K), suggest R2 value in the 15K above, or u a strong push-pull output.
STC12C5204AD ries microcontroller programmable counter array
(PCA)
PCA contains a special 16 timer, has four 16 bits of capture/comparison of module and connected. Each module programmable work
In four mode: increa/decrea along the capture, software timer, high-speed output or could be modulated pul output. Modules connected to P3.7 (0 CEX0 / PCA0 / PWM0), module 1 connected to P3.5 (CEX1 / PCA1 / PWM1), modules connected to P2.0 (2 CEX2 / PCA2 / PWM2), modules connected to P2.4 (3 CEX3 / PCA3 / PWM3). Register the content of CH and CL is free of 16 PCA increasing count the value of the timer. PCA timer is four modules, the public time benchmark by programming work .大连电脑培训学校
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eProgrammable Counter Array
