电工电子类外文翻译---芯片STC12C5204AD的IO口配置.doc

Chip STC12C5204AD I/O port configuration STC12C5204AD series 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 series 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 used as output and input function but dont need to reconfigure mouth lines output state. This is because 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 itself 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 close 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 infused 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 c