Hello everyone, I am Chris, the field application engineer from Nuvoton Technology. Today, I will introduce the application and principle of programmable seriel I/O aka PSIO on M251/M252. The programmable serial I/O of NuMicro M251/M252 series can generate arbitrary waveforms and combine them to achieve data transmission and reception of specific serial communication protocols. Of course, standard serial communication can also be achieved, such as UART SPI I2C Usually, it is common to use Timer+GPIO to achieve these specific communication protocols, but it is more complicated and requires frequent CPU intervention. When we use PSIO, this not only simplifies the complexity of the operation but also reduces the burden on the CPU. The saved CPU performance could be distributed in other places. Since all hardware operations do not require software intervention, the timing control is more precise. The principle of PSIO is to use a slot controller to control the pin input and output or determine the state, and it can also control the duration of these states. Each slot controller has eight slots, which can be used as eight settings, and the registers corresponding to each slot can access the data that needs to be input and output, and can also set the time for the current pin to maintain this state. Each slot can reach a checkpoint, usually 1 to 1, 2 to 2, 3 to 3, and so on. Each checkpoint can set the pin status of the corresponding slot within the corresponding time. Next, let’s take a look at a simple output-only example In the initial stage, we first set the state of the pin to be high before SLOT has started, so the output is high Then when the Slot controller receives the start signal, SLOT0 is set to output low level according to the setting of CP0 and waits for the time of SLOT0 to expire. Then SLOT1 is set to output low level according to the setting of CP1 and waits for the time of SLOT1 to expire. And so on, followed by SLOT2 output low level SLOT3 low level SLOT4 high level SLOT5 high level After SLOT5, since SLOT6 is not set, the waveform of the protocol can be completed with only six slots Between the time of the next data transmission, we set the interval low, so the output is low at this time Users can complete different protocols according to these simple operations. In the related resources section, we have provided two PSIO application notes. There are two protocol examples with more detailed operations and descriptions. If you want to know more details about PSIO, please download it from the URL in the video. Several sample codes of different protocols are also provided in BSP. That’s all for this tutorial. Thank you for watching it. Welcome to subscribe to our channel. If you want to know more information, please contact us. #Tool #Training #Learning #Intermediate #en - For more information, please visit Nuvoton Technology Website: https://bit.ly/3hVdcmC Buy now: https://direct.nuvoton.com/numaker-m251sd Contact us: SalesSupport@nuvoton.com