Neoway N21 Series Hardware User's Manual

Neoway N21 Series Hardware User's Manual Manual pdf 21 page image

N21Hardware User GuideCopyright © Neoway Technology Co., Ltd. All rights reserved. 12Startup ProcessAfter powering up the VBAT pin, input low level for 1.2 second at PWRKEY_N to start the module. PullPWRKEY_N high after the module is started. The STATUS indicator turns on, indicating that themodule completes initialization. The baud rate of N21 is flexible since the module embeds automaticbaud rate detection. Before sending data through UART port, issue AT so that the UART port canautomatically detects the baud rate and outputs +PBREADY, indicating that the UART is ready.In program design, use +PBREADY to check whether the module is reset due to any fault.To use the function of automatic startup once powered up, refer to Figure 3-5. Note that this startupdesign does not support shutdown.Prior to turning on the module, power on the host MCU and complete the UART initialization.Otherwise conflicts may occur during initialization due to unstable conditions.Figure 3-6 Startup timingVBATPWRKEY_NUART3s1.2sNo power failure is allowed during initialization. Otherwise, the hardware might encounter faults or bedamaged.Shutdown ProcessThe module can be powered off through hardware and software.PWRKEY_N is used to hardware shut down the module. When the module is working, inputtingnegative pulses for more than 500 ms to PWRKEY_N can trigger the shutdown process of the module.The module is shut down after around 2 seconds, and then turns off the power supply.Figure 3-10 shows the hardware shutdown timing.