TO2440int启动代码详解及配置注解

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该资源是一份名为"2440INIT.S"的启动代码注解文件,主要针对TQ2440int处理器进行初始化配置。该文件主要用于嵌入式系统开发,特别是使用ARM架构的TQ2440微控制器。以下是从标题和描述中提炼出的关键知识点: 1. 代码结构: - 文件名 "2440INIT.S" 表明这是一个用于TQ2440int处理器的初始化代码示例,可能是用于引导程序或系统启动过程。 2. 内存配置: - 包含了GEToption.inc和GETmemcfg.inc两个外部配置文件,用于设置内存的选项和配置,确保处理器正确识别和管理内存空间。 3. 自刷新模式: - BIT_SELFREFRESHEQU宏定义了一个位(1<<22),指示是否启用ARM的自我刷新功能,这对于某些低功耗应用可能很重要。 4. 预定义常量: - 用户模式(USERMODEEQU)、快速中断模式(FIQMODEEQU)、中断请求模式(IRQMODEEQU)、系统管理模式(SVCMODEEQU)、未定义模式(UNDEFMODEEQU)和模式标志(MODEMASK)被定义,用于处理不同运行模式下的处理器行为。 5. 堆栈布局: - 定义了不同级别的堆栈地址,如用户栈(UserStack)、系统服务栈(SVCStack)、未定义模式栈(UndefStack)、异常堆栈(AbortStack)、中断堆栈(IRQStack)和快速中断堆栈(FIQStack),这些堆栈对任务调度和异常处理至关重要。 6. Thumb代码支持: - 文件检查是否使用了THUMB代码(16位),如果使用,则设置THUMBCODESETL宏,以决定是否启用16位或32位代码执行模式。 7. 宏定义: - MACRO MOV_PC_LR 是一个宏,可能用于在代码中简化处理器从当前地址跳转到子程序返回地址的操作,对于高效编程非常实用。 这份启动代码注解提供了详细的处理器初始化步骤和堆栈管理,对于理解和调试基于TQ2440int的嵌入式系统项目具有重要意义。通过阅读和理解这部分代码,开发人员可以配置处理器的工作环境、堆栈大小以及优化代码执行模式,从而确保系统的稳定性和性能。

详细解释以下Python代码:import numpy as np import adi import matplotlib.pyplot as plt sample_rate = 1e6 # Hz center_freq = 915e6 # Hz num_samps = 100000 # number of samples per call to rx() sdr = adi.Pluto("ip:192.168.2.1") sdr.sample_rate = int(sample_rate) # Config Tx sdr.tx_rf_bandwidth = int(sample_rate) # filter cutoff, just set it to the same as sample rate sdr.tx_lo = int(center_freq) sdr.tx_hardwaregain_chan0 = -50 # Increase to increase tx power, valid range is -90 to 0 dB # Config Rx sdr.rx_lo = int(center_freq) sdr.rx_rf_bandwidth = int(sample_rate) sdr.rx_buffer_size = num_samps sdr.gain_control_mode_chan0 = 'manual' sdr.rx_hardwaregain_chan0 = 0.0 # dB, increase to increase the receive gain, but be careful not to saturate the ADC # Create transmit waveform (QPSK, 16 samples per symbol) num_symbols = 1000 x_int = np.random.randint(0, 4, num_symbols) # 0 to 3 x_degrees = x_int*360/4.0 + 45 # 45, 135, 225, 315 degrees x_radians = x_degrees*np.pi/180.0 # sin() and cos() takes in radians x_symbols = np.cos(x_radians) + 1j*np.sin(x_radians) # this produces our QPSK complex symbols samples = np.repeat(x_symbols, 16) # 16 samples per symbol (rectangular pulses) samples *= 2**14 # The PlutoSDR expects samples to be between -2^14 and +2^14, not -1 and +1 like some SDRs # Start the transmitter sdr.tx_cyclic_buffer = True # Enable cyclic buffers sdr.tx(samples) # start transmitting # Clear buffer just to be safe for i in range (0, 10): raw_data = sdr.rx() # Receive samples rx_samples = sdr.rx() print(rx_samples) # Stop transmitting sdr.tx_destroy_buffer() # Calculate power spectral density (frequency domain version of signal) psd = np.abs(np.fft.fftshift(np.fft.fft(rx_samples)))**2 psd_dB = 10*np.log10(psd) f = np.linspace(sample_rate/-2, sample_rate/2, len(psd)) # Plot time domain plt.figure(0) plt.plot(np.real(rx_samples[::100])) plt.plot(np.imag(rx_samples[::100])) plt.xlabel("Time") # Plot freq domain plt.figure(1) plt.plot(f/1e6, psd_dB) plt.xlabel("Frequency [MHz]") plt.ylabel("PSD") plt.show(),并分析该代码中QPSK信号的功率谱密度图的特点

2023-06-06 上传

帮我用中文注释一下代码:// ThreadTester.java // Multiple threads printing at different intervals. public class ThreadTester { public static void main( String [] args ) { // create and name each thread PrintThread thread1 = new PrintThread( "thread1" ); PrintThread thread2 = new PrintThread( "thread2" ); PrintThread thread3 = new PrintThread( "thread3" ); System.err.println( "主线程将要启动三个线程" ); thread1.start(); // start thread1 and place it in ready state thread2.start(); // start thread2 and place it in ready state thread3.start(); // start thread3 and place it in ready state System.err.println( "三个线程启动完成, 主线程运行结束\n" ); } // end main } // end class ThreadTester // class PrintThread controls thread execution class PrintThread extends Thread { private int sleepTime; // assign name to thread by calling superclass constructor public PrintThread( String name ) { super( name ); // pick random sleep time between 0 and 5 seconds sleepTime = ( int ) ( Math.random() * 5001 ); } // method run is the code to be executed by new thread public void run() { // put thread to sleep for sleepTime amount of time try { System.err.println( getName() + " 进入睡眠状态,睡眠时间是: " + sleepTime ); Thread.sleep( sleepTime ); } // if thread interrupted during sleep, print stack trace catch ( InterruptedException exception ) { } // print thread name System.err.println( getName() + " 睡眠醒来" ); } // end method run } // end class PrintThread

2023-06-06 上传