wenkong_junshi/Examples/TIMER/TIMER2_inputcapture

/*!
\file readme.txt
\brief description of the TIMER2 input capture demo for gd32f30x

\version 2017-02-10, V1.0.0, firmware for GD32F30x
\version 2018-10-10, V1.1.0, firmware for GD32F30x
\version 2018-12-25, V2.0.0, firmware for GD32F30x
\version 2020-09-30, V2.1.0, firmware for GD32F30x
*/

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*/

This demo is based on the GD32307C-EVAL-V1.1 board, it shows TIMER peripheral to
measure the frequency of an external signal.

The TIMxCLK frequency is set to systemcoreclock,the prescaler is 120 so
the TIMER2 counter clock is 1MHz.

The external signal is connected to TIMER2 CH0 pin (PA6).
The rising edge is used as active edge.
The TIMER2 CH0CV is used to compute the frequency value.

The available frequence of the input signal is ranging from 16Hz to 20KHz.
You can use USART to watch the frequency of the input signal.The USART is
configured as follow:
- BaudRate = 115200 baud
- Word Length = 8 Bits
- One Stop Bit
- No parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled