2, ~20mA after 250Ω sampling resistance can be converted into 1~5V. Then use the subtracter circuit, subtract 1V from the output, you can get 0~4V. Change the gain of the subtracter circuit to 3/4, you can get 0~3V output. The circuit is as follows: In the figure above, ui1 is connected to 1V, and Ui2 is connected to 1~5V.
3, so that you can output a -3V signal at 20mA, to output 0V at 4mA, the op amp inverting end also has a tunerZero voltage, and finally reverse the output voltage again. The output is 3V-0V and can be connected to the AD port of the STM32F.
4, the range of STM32 pin input level is 0-6V. The VDD voltage range is 0V-6V, with external power supplied via VDD pins for I/O and internal regulators.
1, the rest of the IO ports on the function port (such as GPIOA) are not used as ordinary IO outputs (because it is a keyboard scan, when the column output, the row should be input; Similarly, when a column is input, the GPIO port outside the output) column is either a normal IO input port or a functional port.
2, VDD is the main power supply, but also the input power of the IO port output level. VDDA is an analog power supply when using analog signals, such as AD (modulus) or DA (digital mode)), the system will use the VDDA voltage as a reference voltage.
3, serial input we can choose the chip 74HC, 74LS, TPIC6B. However, 74HC and 74LS two chips must be driven to drive the LED, and TI's DMOS device TPIC6B, in addition to the logic function of TTL and CMOS devices shift register, its biggest feature is that the drive power is large, can be directly used as the driver of LED.
Single chip microcomputer model: STM32F103VET6AD 12bit resolution three-channel ADC MDA has data, but the data fluctuates greatly, with 0-4096 as the range, and the fluctuation is positive or negative 50-80. The power supply for both the MCU and ADC is provided by the 7805 via the AMS1117-3V. The 7805 is powered by a 12VDC TO DC step-down chip.
ADC resolution setting error: When configuring ADC, willThe resolution is set to 12 bits instead of 8. Ensure that the ADC resolution is set correctly during the hardware configuration phase. Data conversion error: An incorrect data conversion was performed after reading data from the ADC. For example, the data of a 12-bit ADC is incorrectly converted to 8-bit data.
Start conversion: Start the conversion process by setting the ADON bit and SWSTART bit in the ADC's CR2 register. The ADON bit is used to enable the ADC and the SWSTART bit is used to start the conversion. Wait for the conversion to complete: you can determine the conversion by querying the EOC bit of the conversion status register as required