信号发生器

电子设计作品报告姓名：班级：电子1102班信号发生器姓名：摘要本设计以ATxmega256A3BU单片机为中心控制系统，由液晶显示模块、波形产生模块、幅度放大模块组成。

通过按键切换三种输出波形（方波、三角波、正弦波）。

对于改变频率，设定四种工作模式。

通过按键，对产生波形的频率在20Hz到9999Hz的范围内分别可以进行步长为5Hz频率加减调频、步长为1Hz频率加减调频、逐位调频（通过按键，分别对频率数字的每一位进行调节）以及频率锁死工作模式。

通过LED0、LED1以及LCD500的亮灭组合来指示不同的工作模式。

在LCD500屏幕上，能同步显示输出波形名称、频率、改变频率模式以及作者中英文姓名。

波形输出引脚依次与滤波器和放大器相连接，通过调节放大器可变电阻改变波形幅值，使波形幅值在1v到5v内调节。

一、系统方案1、信号发生对三个波形，通过数学计算，分别对方波、三角波、正弦波三个波形每周期各自取32个采样点。

在Atmel Studio编译环境下，对ATxmega256A3BU进行编程。

把三个波形的数据分别赋值于三个16位无符号整型数组内，每个数组32个元素。

如图1.1所示，利用单片机DAC模块，在XMEGA-A3BU Xplained板上的J2的第二个引脚输出的波形。

通过编程，使手动对SW1按键的电位变化分别调用存有三个波形的数组，利用按键SW1循环选择输出方波、三角波、正弦波。

图1.1 XMEGA-A3BU Xplained板面示意图2、频率改变单片机晶振基准频率为32MHz,令 n f f N f f N F N /,/0==其中，0f 为输出频率，F f 为晶振基准频率，N f 为基准频率经分频器分频后的值，N 为分频器的分频系数，n 为输出波形每周期采样点数。

本系统实质通过按键改变N 和n 来改变输出频率。

3、显示模块利用XMEGA-A3BU Xplained 板上自备的LCD500显示。

LCD 液晶不但能显示中文字符、英文字符和数字，而且显示效果较好，容易编程实现。

4、幅值改变由于通过编写程序，只能使XMEGA-A3BU Xplained 板输出波形幅值在0到1v 内变化。

所以，将 XMEGA-A3BU Xplained 板波形输出引脚接入20Hz 到20000Hz 帯通滤波器再接入2级放大器输出。

通过改变放大器的可变电阻，使输出波形幅值在1v 到5v 之间进行自由的变换 。

二、系统设计1、总体设计思路通过ATxmega256A3BU 单片机，控制波形切换、频率改变、液晶显示；通过控制放大器可变电阻控制输出波形幅值。

系统如图2.1所示。

图2.1 系统简示图2、波形选择及频率改变模块根据采样定理，周期性波形单个周期采样频率大于周期波自身频率二倍。

经测试，当每个波形每周期为32个采样点时能在0——3000Hz 内良好输出波形； 当每个波形每周期为16个采样点时能在0——6000Hz 内良好输出波形；当每个波形每周期为8个采样点时能在0——12000Hz 内良好输出波形； 当每个波形每周期为4个采样点时能在0——24000Hz 内输出波形，但此时失真较明显。

因此，本系统采用当输出频率小于2000Hz 时，每个波每周期输出32个数据； 当输出频率在2000Hz 到4500Hz 时，每个波每周期输出16个数据；当输出频率在4500Hz 到10000Hz 时，每个波每周期输出8个数据。

256A3BU 单片机 滤波器 放大器 LCD500 显示波形输出当初始化时，输出频率为20Hz的方波同时LCD屏幕显示频率与与输出波形。

根据图1.1，通过按键SW1，可使输出波形可依次在方波、三角波、正弦波和无输出信号状态下循环，并在屏幕上同步显示输出波的类型。

等步长频率调节模式：最开始，频率调节是处于锁死状态。

按键SW0，LED0和LCD亮，表示进入5Hz频率增加调节模式。

此时，按键SW2可改变波形频率，每次增加步长为5Hz，屏幕同步显示改变频率。

第二次按键SW0，表LED0和LCD亮，表示进入5Hz频率减小调节模式。

此时，按键SW2可改变波形频率，每次减小步长为5Hz，屏幕同步显示改变频率。

第三次按键SW0，表LED1和LCD亮，表示进入1Hz频率增加调节模式。

此时，按键SW2可改变波形频率，每次增加步长为1Hz，屏幕同步显示改变频率。

第四次按键SW0，表LED1和LCD亮，表示进入5Hz频率减小调节模式。

此时，按键SW2可改变波形频率，每次减小步长为1Hz，屏幕同步显示改变频率。

第五次按键SW0，回到锁死状态，所有灯灭掉。

此时完成一个频率调节模式循环。

逐位调频模式：由于步长为5Hz和1Hz频率调节，对于较大频率调节过程比较繁琐，所以本系统设计了逐位改变频率模式。

按键SW0，使系统处于锁死状态。

按键SW1，使波形输出到无信号输出状态。

再通过按键SW2可对输出频率个位数字进行设置，并在LCD上显示。

同理，此时按键SW0可依次进入对频率十位、百位、千位数字改变模式，并在LCD上显示工作状态。

在不同位数调节模式下，通过按键SW2可分别对各个位数上数字进行设置。

设置好输出频率后，按键SW1选择输出波形，可输出设置频率的特定波形。

3、液晶显示模块图2.2 LCD 500电路连接图通过程序点阵输入，使ATxmega256A3BU单片机控制液晶显示能同步显示输出波的类型，频率，调节模式，能同时显示汉字、英文字符、数字。

4、幅度放大模块我们通过改变放大器可变电阻来，使最终波形在幅值在1v到5v内改变。

我们输出的信号为小信号，如果想要在1v到5v之间进行自由的变换，就需要放大器进行放大，所以我们设计了一个放大电路。

我们采用了2级放大电路，经过第一级的放大之后进入第二级，第二级中我们采用了可变电阻通过电阻阻值的改变而改变第二级放大的倍数，一级与二级放大倍数乘积就是放大倍数，从而实现放大倍数的可调，使我们输出的电压能够在1v到5v之间改变。

为了实现一个通带我20hz到20khz的带通滤波器，我们用Filter Solutions 软件先设计了一个高通滤波器，使其截至频率为20Hz，大于20Hz频率的波能够通过，我们接着又用Filter Solutions设计了一个低通滤波器，使其截至频率为20KHz，当大于20KHz的波通过时会被滤掉，将2个滤波器连接后使用，这样就实现了通带为20Hz到20khz的带通滤波器。

仿真后用扫描仪观察即可。

由于系统从XMEGA-A3BU Xplained板输出波形幅值小于1v,所以我们给定我们给出一个电压为1v，频率为1KHz的交流正弦电源输入，仿真电路如下。

放大器电路仿真截图：图2.3 放大器仿真电路图滤波器仿真截图：图2.4 滤波器仿真电路图三、软件设计程序全部由C 语言编写，可实现波形类型的选择、频率档位、电压输入、频率步进值和电压初值的设定,显示部分可实时显示输出信号的类型、频率和频率步进值。

主程序流程图，如图2.5所示。

图2.5 主程序流程图 控制输入 设定波形输出，输出性质显示 方波 三角波 正弦波 开始初始化显示， 预设波形输出 等待近键按键识别波形选择 频率控制 幅度控制四、测试1、输出波形频率测试设置频率(Hz) 液晶显示频率(Hz) 输出频率（Hz)20 20 201000 1000 1000.52000 2000 20014000 4000 4000.55000 5000 50007000 7000 70009999 9999 9999表4.1 输出波形频率测试表2、输出波形幅度范围测试测试方法与过程：对于放大器和滤波器，我们都先采用multisim仿真软件进行仿真测试。

测试软件：multisim仿真软件测试结果：放大器：用软件我们给了一个能发出500mv电压，1khz频率的电源，通过改变可变电阻，实现对电压的放大，实现在我们输出电压能够经过放大在1v---5v范围内自由改变。

可变电97 95 94 92 91 90 88 87 85阻改变值（%）1.036 1.7272.072 2.7633.109 3.4544.145 4.4915.182 放大电压（v）表4.2 波形幅值输出仿真测试五、结论我们以ATxmega256A3BU单片机为核心控制，通过可编程放大电路实现了正弦波、方波、三角波的输出功能。

其频率能在0——10000Hz内自由输出，实现了等步距调节和逐位调节。

幅度能在1到5v内自由变化。

并实现液晶屏幕同步显示改变信息。

在系统的设计过程中，力求硬件电路简单，充分发挥软件编程方便灵活的特点，并最大限度挖掘单片机的资源。

C程序：#include <asf.h>//一定要有#include <board.h>#include <sysclk.h>#include <st7565r.h>#define my_button0 IOPORT_CREATE_PIN(PORTE,5) #define my_button1 IOPORT_CREATE_PIN(PORTF,1)#define my_button2 IOPORT_CREATE_PIN(PORTF,2)#define SPEAKER_DAC DACB#define SPEAKER_DAC_CHANNEL DAC_CH0#define NR_OF_SAMPLES 32char table_character[][6]={{0x00,0x00,0x00,0x00,0x00,0x00, }, // space { 0x00, 0x00, 0x00, 0x2f, 0x00, 0x00 }, // ! { 0x00, 0x00, 0x07, 0x00, 0x07, 0x00 }, // " { 0x00, 0x14, 0x7f, 0x14, 0x7f, 0x14 }, // # { 0x00, 0x24, 0x2a, 0x7f, 0x2a, 0x12 }, // $ { 0x00, 0x62, 0x64, 0x08, 0x13, 0x23 }, // % { 0x00, 0x36, 0x49, 0x55, 0x22, 0x50 }, // & { 0x00, 0x00, 0x05, 0x03, 0x00, 0x00 }, // ' { 0x00, 0x00, 0x1c, 0x22, 0x41, 0x00 }, // ( { 0x00, 0x00, 0x41, 0x22, 0x1c, 0x00 }, // ) { 0x00, 0x14, 0x08, 0x3E, 0x08, 0x14 }, // * { 0x00, 0x08, 0x08, 0x3E, 0x08, 0x08 }, // + { 0x00, 0x00, 0x00, 0xA0, 0x60, 0x00 }, // , { 0x00, 0x08, 0x08, 0x08, 0x08, 0x08 }, // - { 0x00, 0x00, 0x60, 0x60, 0x00, 0x00 }, // . { 0x00, 0x20, 0x10, 0x08, 0x04, 0x02 }, // / { 0x00, 0x3E, 0x51, 0x49, 0x45, 0x3E }, // 0 { 0x00, 0x00, 0x42, 0x7F, 0x40, 0x00 }, // 1 { 0x00, 0x42, 0x61, 0x51, 0x49, 0x46 }, // 2 { 0x00, 0x21, 0x41, 0x45, 0x4B, 0x31 }, // 3 { 0x00, 0x18, 0x14, 0x12, 0x7F, 0x10 }, // 4{ 0x00, 0x3C, 0x4A, 0x49, 0x49, 0x30 }, // 6 { 0x00, 0x01, 0x71, 0x09, 0x05, 0x03 }, // 7 { 0x00, 0x36, 0x49, 0x49, 0x49, 0x36 }, // 8 { 0x00, 0x06, 0x49, 0x49, 0x29, 0x1E }, // 9 { 0x00, 0x00, 0x36, 0x36, 0x00, 0x00 }, // : { 0x00, 0x00, 0x56, 0x36, 0x00, 0x00 }, // ; { 0x00, 0x08, 0x14, 0x22, 0x41, 0x00 }, // < { 0x00, 0x14, 0x14, 0x14, 0x14, 0x14 }, // = { 0x00, 0x00, 0x41, 0x22, 0x14, 0x08 }, // > { 0x00, 0x02, 0x01, 0x51, 0x09, 0x06 }, // ? { 0x00, 0x32, 0x49, 0x59, 0x51, 0x3E }, // @ { 0x00, 0x7C, 0x12, 0x11, 0x12, 0x7C }, // A { 0x00, 0x7F, 0x49, 0x49, 0x49, 0x36 }, // B { 0x00, 0x3E, 0x41, 0x41, 0x41, 0x22 }, // C { 0x00, 0x7F, 0x41, 0x41, 0x22, 0x1C }, // D { 0x00, 0x7F, 0x49, 0x49, 0x49, 0x41 }, // E { 0x00, 0x7F, 0x09, 0x09, 0x09, 0x01 }, // F { 0x00, 0x3E, 0x41, 0x49, 0x49, 0x7A }, // G { 0x00, 0x7F, 0x08, 0x08, 0x08, 0x7F }, // H { 0x00, 0x00, 0x41, 0x7F, 0x41, 0x00 }, // I { 0x00, 0x20, 0x40, 0x41, 0x3F, 0x01 }, // J { 0x00, 0x7F, 0x08, 0x14, 0x22, 0x41 }, // K { 0x00, 0x7F, 0x40, 0x40, 0x40, 0x40 }, // L { 0x00, 0x7F, 0x02, 0x0C, 0x02, 0x7F }, // M { 0x00, 0x7F, 0x04, 0x08, 0x10, 0x7F }, // N { 0x00, 0x3E, 0x41, 0x41, 0x41, 0x3E }, // O { 0x00, 0x7F, 0x09, 0x09, 0x09, 0x06 }, // P { 0x00, 0x3E, 0x41, 0x51, 0x21, 0x5E }, // Q { 0x00, 0x7F, 0x09, 0x19, 0x29, 0x46 }, // R { 0x00, 0x46, 0x49, 0x49, 0x49, 0x31 }, // S { 0x00, 0x01, 0x01, 0x7F, 0x01, 0x01 }, // T { 0x00, 0x3F, 0x40, 0x40, 0x40, 0x3F }, // U { 0x00, 0x1F, 0x20, 0x40, 0x20, 0x1F }, // V { 0x00, 0x3F, 0x40, 0x38, 0x40, 0x3F }, // W { 0x00, 0x63, 0x14, 0x08, 0x14, 0x63 }, // X { 0x00, 0x07, 0x08, 0x70, 0x08, 0x07 }, // Y { 0x00, 0x61, 0x51, 0x49, 0x45, 0x43 }, // Z { 0x00, 0x00, 0x7F, 0x41, 0x41, 0x00 }, // [ { 0x00, 0x55, 0x2A, 0x55, 0x2A, 0x55 }, // 55 { 0x00, 0x00, 0x41, 0x41, 0x7F, 0x00 }, // ] { 0x00, 0x04, 0x02, 0x01, 0x02, 0x04 }, // ^ { 0x00, 0x40, 0x40, 0x40, 0x40, 0x40 }, // _ { 0x00, 0x00, 0x01, 0x02, 0x04, 0x00 }, // '{ 0x00, 0x7F, 0x48, 0x44, 0x44, 0x38 }, // b{ 0x00, 0x38, 0x44, 0x44, 0x44, 0x20 }, // c{ 0x00, 0x38, 0x44, 0x44, 0x48, 0x7F }, // d{ 0x00, 0x38, 0x54, 0x54, 0x54, 0x18 }, // e{ 0x00, 0x08, 0x7E, 0x09, 0x01, 0x02 }, // f{ 0x00, 0x18, 0xA4, 0xA4, 0xA4, 0x7C }, // g{ 0x00, 0x7F, 0x08, 0x04, 0x04, 0x78 }, // h{ 0x00, 0x00, 0x44, 0x7D, 0x40, 0x00 }, // i{ 0x00, 0x40, 0x80, 0x84, 0x7D, 0x00 }, // j{ 0x00, 0x7F, 0x10, 0x28, 0x44, 0x00 }, // k{ 0x00, 0x00, 0x41, 0x7F, 0x40, 0x00 }, // l{ 0x00, 0x7C, 0x04, 0x18, 0x04, 0x78 }, // m{ 0x00, 0x7C, 0x08, 0x04, 0x04, 0x78 }, // n{ 0x00, 0x38, 0x44, 0x44, 0x44, 0x38 }, // o{ 0x00, 0xFC, 0x24, 0x24, 0x24, 0x18 }, // p{ 0x00, 0x18, 0x24, 0x24, 0x18, 0xFC }, // q{ 0x00, 0x7C, 0x08, 0x04, 0x04, 0x08 }, // r{ 0x00, 0x48, 0x54, 0x54, 0x54, 0x20 }, // s{ 0x00, 0x04, 0x3F, 0x44, 0x40, 0x20 }, // t{ 0x00, 0x3C, 0x40, 0x40, 0x20, 0x7C }, // u{ 0x00, 0x1C, 0x20, 0x40, 0x20, 0x1C }, // v{ 0x00, 0x3C, 0x40, 0x30, 0x40, 0x3C }, // w{ 0x00, 0x44, 0x28, 0x10, 0x28, 0x44 }, // x{ 0x00, 0x1C, 0xA0, 0xA0, 0xA0, 0x7C }, // y{ 0x00, 0x44, 0x64, 0x54, 0x4C, 0x44 }, // z{ 0x14, 0x14, 0x14, 0x14, 0x14, 0x14 } // horiz lines };static const uint16_t square[NR_OF_SAMPLES] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,30000,};static const uint16_t triangle[NR_OF_SAMPLES] = {0, 4096, 8192, 12287, 16384, 20480, 24576, 28672,32768, 36864, 40960, 45056, 49151, 53248, 57343, 61440, 65535, 61440, 57343, 53248, 49151, 45056, 40960, 36864, 32768, 28672, 24576, 20480, 16384, 12287, 8192, 4096,};static const uint16_t sine[NR_OF_SAMPLES] = {32768, 35327, 37784, 40050, 42036, 43666, 44877, 45623,45875, 45623, 44877, 43666, 42036, 40050, 37784, 35325,32771, 30211, 27752, 25486, 23500, 21870, 20659, 19913,19661, 19913, 20659, 21870, 23500, 25486, 27752, 30211,};char able_character[][8]={0x10,0xFF,0x91,0xFF,0x38,0x74,0xD3,0x10,0x7E,0x7E,0x42,0x7E,0xFF,0x2C,0x38,0xEF,0xFF,0x8,0xFF,0xAD,0x89,0xAD,0x89,0x83,0xFF,0x8,0xFF,0xAD,0x89,0xAD,0x89,0x83,0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,0x10,0xFE,0xFE,0x48,0x7E,0x8,0x4A,0x99,0x54,0x74,0x75,0xFF,0x5C,0x74,0x54,0x54,0x10,0xFF,0x74,0xFF,0x18,0xFF,0x10,0x30,0x28,0x28,0xEE,0x2C,0x28,0x28,0xE9,0x2E,0x10,0x10,0xFF,0x18,0x18,0x24,0xC6,0x83,0x52,0x54,0xFF,0xFD,0x7C,0xFF,0x8,0x38,0x10,0xFF,0x28,0x48,0x7E,0x2C,0x4A,0x99};static void evsys_init(void){sysclk_enable_module(SYSCLK_PORT_GEN, SYSCLK_EVSYS);EVSYS.CH3MUX = EVSYS_CHMUX_TCC0_OVF_gc;}void tc_init(void){tc_enable(&TCC0);tc_set_wgm(&TCC0, TC_WG_NORMAL);tc_write_period(&TCC0,427755000.0/BOARD_XOSC_HZ);tc_write_clock_source(&TCC0, TC_CLKSEL_DIV1_gc);}void dac_init(void){struct dac_config conf;dac_read_configuration(&SPEAKER_DAC, &conf);dac_set_conversion_parameters(&conf, DAC_REF_BANDGAP,DAC_ADJ_LEFT);dac_set_active_channel(&conf, SPEAKER_DAC_CHANNEL, 0);dac_set_conversion_trigger(&conf, SPEAKER_DAC_CHANNEL, 3);#ifdef XMEGA_DAC_VERSION_1dac_set_conversion_interval(&conf, 1);#endifdac_write_configuration(&SPEAKER_DAC, &conf);dac_enable(&SPEAKER_DAC);}void write_string(uint8_t page,uint8_t startline,char *pString) {uint8_t i;st7565r_set_page_address(page);st7565r_set_column_address(startline);while (*pString){for (i=0;i<6;i++){st7565r_write_data(table_character[*pString-32][i]);}pString++;}}void write_smy(uint8_t page,uint8_t startline,char *pString){uint8_t i;st7565r_set_page_address(page);st7565r_set_column_address(startline);while (*pString){for (i=0;i<8;i++){st7565r_write_data(able_character[*pString-32][i]);}pString++;}}int main(void){//! the page address to write touint8_t page_address;//! the column address, or the X pixel.uint8_t column_address;//! store the LCD controller start draw lineuint8_t start_line_address = 0;//! value used for delay, needs to be volatile due to compiler optimizationboard_init();sysclk_init();ioport_init();evsys_init();tc_init();dac_init();delay_init();ioport_set_pin_dir(my_button1,IOPORT_DIR_INPUT);ioport_set_pin_mode(my_button1, IOPORT_MODE_PULLUP);ioport_set_pin_dir(my_button2,IOPORT_DIR_INPUT);ioport_set_pin_mode(my_button2, IOPORT_MODE_PULLUP);ioport_set_pin_dir(my_button0,IOPORT_DIR_INPUT);ioport_set_pin_mode(my_button0, IOPORT_MODE_PULLUP);st7565r_init();// set addresses at beginning of displayst7565r_set_page_address(0);st7565r_set_column_address(0);// 清屏一下,否则可能出现乱点for (page_address = 0; page_address <= 8; page_address++) { st7565r_set_page_address(page_address);for (column_address = 0; column_address < 128; column_address++) {st7565r_set_column_address(column_address);/* fill every other pixel in the display. This will producehorizontal lines on the display. */st7565r_write_data(0x00);}}st7565r_set_display_start_line_address(0X00);//write_smy(3,5," $!$#$$+$($)$*");write_string(2,5,"Mr Li, Mr Liang");write_string(0,5,"Frequency(Hz)");write_string(1,67,"0");write_string(1,60,"2");write_string(0,95,"SQ");Bool value0;Bool value1;Bool value2;uint8_t i=0;uint8_t k=0;uint16_t j=0;uint8_t m=0;uint16_t b=0;uint16_t c=0;uint16_t d=0;uint16_t e=0;uint16_t n=0;uint8_t x=0;uint16_t y=0;while(1){ value0= !(ioport_get_pin_level(my_button0));value1 = !(ioport_get_pin_level(my_button1));//断开为1，此处置零value2 = !(ioport_get_pin_level(my_button2));if(value0){m++;m %= 5;if(m==0&&k==3){ write_string(0,95,"x1 ");}else if(m==1&&k==3){ write_string(0,95,"x10 ");}else if(m==2&&k==3){ write_string(0,95,"x100 ");} else if(m==3&&k==3){ write_string(0,95,"x1000 ");}else if(k!=3){switch(k){ case 0:write_string(0,95,"SQ ");break;case 1:write_string(0,95,"Tri ");break;case 2:write_string(0,95,"Sin ");break;case 3:write_string(0,95," ");break;}}delay_ms(500); }ioport_set_pin_level( LED0 ,!((m==1)||(m==2)));ioport_set_pin_level(LED1 ,!((m==3)||(m==4)));ioport_set_pin_level(NHD_C12832A1Z_BACKLIGHT ,m);if(value2) {if(k!=3){if (m==1){ j++;tc_write_period(&TCC0,(1705000000.0/(j+4))/ BOARD_XOSC_HZ);e=j%2;d=(j/2)%10;c=((j+4)/20)%10;b=((j+4)/200)%10;if(e==0){write_string(1,67,"0");}else{write_string(1,67,"5");}switch (d){case 0:write_string(1,60,"2");break;case 1:write_string(1,60,"3");break;case 2:write_string(1,60,"4");break;case 3:write_string(1,60,"5");break;case 4:write_string(1,60,"6");break;case 5:write_string(1,60,"7");break;case 6:write_string(1,60,"8");break;case 7:write_string(1,60,"9");break;case 8:write_string(1,60,"0");break;case 9:write_string(1,60,"1");break;}if(j>15){switch (c){case 0:write_string(1,53,"0");break;case 1:write_string(1,53,"1");break;case 2:write_string(1,53,"2");break;case 3:write_string(1,53,"3");break;case 4:write_string(1,53,"4");break;case 5:write_string(1,53,"5");break;case 6:write_string(1,53,"6");break;case 7:write_string(1,53,"7");break;case 8:write_string(1,53,"8");break;case 9:write_string(1,53,"9");break;}}else{write_string(1,53," ");}if(j>195){switch (b){case 0:write_string(1,46,"0");break;case 1:write_string(1,46,"1");break;case 2:write_string(1,46,"2");break;case 3:write_string(1,46,"3");break;case 4:write_string(1,46,"4");break;case 5:write_string(1,46,"5");break;case 6:write_string(1,46,"6");break;case 7:write_string(1,46,"7");break;case 8:write_string(1,46,"8");break;case 9:write_string(1,46,"9");break;}}else{write_string(1,46," ");}n=(5*j);delay_ms(500);}else if(m==2){ j--;tc_write_period(&TCC0,(1705000000.0/(j+4))/ BOARD_XOSC_HZ );e=j%2;d=(j/2)%10;c=((j+4)/20)%10;b=((j+4)/200)%10;if(e==0){write_string(1,67,"0");}else{write_string(1,67,"5");}switch (d){case 0:write_string(1,60,"2");break;case 1:write_string(1,60,"3");break;case 2:write_string(1,60,"4");break;case 3:write_string(1,60,"5");break;case 4:write_string(1,60,"6");break;case 5:write_string(1,60,"7");break;case 6:write_string(1,60,"8");break;case 7:write_string(1,60,"9");break;case 8:write_string(1,60,"0");break;case 9:write_string(1,60,"1");break;}if(j>15){switch (c){case 0:write_string(1,53,"0");break;case 1:write_string(1,53,"1");break;case 2:write_string(1,53,"2");break;case 3:write_string(1,53,"3");break;case 4:write_string(1,53,"4");break;case 6:write_string(1,53,"6");break;case 7:write_string(1,53,"7");break;case 8:write_string(1,53,"8");break;case 9:write_string(1,53,"9");break;}}else{write_string(1,53," ");}if(j>195){switch (b){case 0:write_string(1,46,"0");break;case 1:write_string(1,46,"1");break;case 2:write_string(1,46,"2");break;case 3:write_string(1,46,"3");break;case 4:write_string(1,46,"4");break;case 5:write_string(1,46,"5");break;case 6:write_string(1,46,"6");break;case 7:write_string(1,46,"7");break;case 8:write_string(1,46,"8");break;case 9:write_string(1,46,"9");break;}} else{write_string(1,46," ");}n=(5*j);delay_ms(500);}else if (m==3){n++;tc_write_period(&TCC0,(853*******.0/(n+20))/ BOARD_XOSC_HZ );e=n%10;d=(n/10)%10;c=((n+20)/100)%10;b=((n+20)/1000)%10;switch(e){ case 0:write_string(1,67,"0");break;case 2:write_string(1,67,"2");break;case 3:write_string(1,67,"3");break;case 4:write_string(1,67,"4");break;case 5:write_string(1,67,"5");break;case 6:write_string(1,67,"6");break;case 7:write_string(1,67,"7");break;case 8:write_string(1,67,"8");break;case 9:write_string(1,67,"9");break;}switch (d){case 0:write_string(1,60,"2");break;case 1:write_string(1,60,"3");break;case 2:write_string(1,60,"4");break;case 3:write_string(1,60,"5");break;case 4:write_string(1,60,"6");break;case 5:write_string(1,60,"7");break;case 6:write_string(1,60,"8");break;case 7:write_string(1,60,"9");break;case 8:write_string(1,60,"0");break;case 9:write_string(1,60,"1");break;}if(n>79){switch (c){case 0:write_string(1,53,"0");break;case 1:write_string(1,53,"1");break;case 2:write_string(1,53,"2");break;case 3:write_string(1,53,"3");break;case 4:write_string(1,53,"4");break;case 5:write_string(1,53,"5");break;case 6:write_string(1,53,"6");break;case 7:write_string(1,53,"7");break;case 8:write_string(1,53,"8");break;case 9:write_string(1,53,"9");break;}}else{write_string(1,53," ");}if(n>879){switch (b){case 0:write_string(1,46,"0");break;case 1:write_string(1,46,"1");break;case 2:write_string(1,46,"2");break;case 3:write_string(1,46,"3");break;case 4:write_string(1,46,"4");break;case 5:write_string(1,46,"5");break;case 6:write_string(1,46,"6");break;case 7:write_string(1,46,"7");break;case 8:write_string(1,46,"8");break;case 9:write_string(1,46,"9");break;}} else if(n<880){write_string(1,46," ");}j=(n/5);delay_ms(500);}else if(m==4){ n--;tc_write_period(&TCC0,(853*******.0/(n+20))/ BOARD_XOSC_HZ );e=n%10;d=(n/10)%10;c=((n+20)/100)%10;b=((n+20)/1000)%10;switch(e){ case 0:write_string(1,67,"0");break;case 1:write_string(1,67,"1");break;case 2:write_string(1,67,"2");break;case 3:write_string(1,67,"3");break;case 4:write_string(1,67,"4");break;case 5:write_string(1,67,"5");break;case 6:write_string(1,67,"6");break;case 7:write_string(1,67,"7");break;case 8:write_string(1,67,"8");break;case 9:write_string(1,67,"9");break;}switch (d){case 0:write_string(1,60,"2");break;case 1:write_string(1,60,"3");break;case 2:write_string(1,60,"4");break;case 3:write_string(1,60,"5");break;case 4:write_string(1,60,"6");break;case 5:write_string(1,60,"7");break;case 6:write_string(1,60,"8");break;case 7:write_string(1,60,"9");break;case 8:write_string(1,60,"0");break;case 9:write_string(1,60,"1");break;}if(n>79){switch (c){case 0:write_string(1,53,"0");break;case 1:write_string(1,53,"1");break;case 2:write_string(1,53,"2");break;case 3:write_string(1,53,"3");break;case 4:write_string(1,53,"4");break;case 5:write_string(1,53,"5");break;case 6:write_string(1,53,"6");break;case 7:write_string(1,53,"7");break;case 8:write_string(1,53,"8");break;case 9:write_string(1,53,"9");break;}}else{write_string(1,53," ");}if(n>879){switch (b){case 0:write_string(1,46,"0");break;case 1:write_string(1,46,"1");break;case 2:write_string(1,46,"2");break;case 3:write_string(1,46,"3");break;case 4:write_string(1,46,"4");break;case 5:write_string(1,46,"5");break;case 6:write_string(1,46,"6");break;case 7:write_string(1,46,"7");break;case 8:write_string(1,46,"8");break;case 9:write_string(1,46,"9");break;}} else if(n<880){write_string(1,46," ");}j=(n/5);delay_ms(500);}}else if(k==3){if(x!=10){if(m==0){e=x;}else if(m==1){d=10*x;}else if(m==2){c=100*x;}else if (m==3){b=1000*x;}}else if(x==10){if(m==0){e=0;}else if(m==1){d=0;}else if(m==2){c=0;}else if (m==3){b=0;}}if(m!=4){switch(x){case 0:write_string(1,67-m*7,"0");break;case 1:write_string(1,67-m*7,"1");break;case 2:write_string(1,67-m*7,"2");break;case 3:write_string(1,67-m*7,"3");break;case 4:write_string(1,67-m*7,"4");break;case 5:write_string(1,67-m*7,"5");break;case 6:write_string(1,67-m*7,"6");break;case 7:write_string(1,67-m*7,"7");break;case 8:write_string(1,67-m*7,"8");break;case 9:write_string(1,67-m*7,"9");break;case 10:write_string(1,67-m*7," ");break;}}y=b+c+d+e;if(y<2000){tc_write_period(&TCC0,(8505500000.0/y)/ BOARD_XOSC_HZ );}else if((y>1999)&&(y<4500)){tc_write_period(&TCC0,(17033000000.0/y)/ BOARD_XOSC_HZ );}else if(y>4499){tc_write_period(&TCC0,(33977000000.0/y)/ BOARD_XOSC_HZ );}x++;x%=11;delay_ms(500);}}if(value1){k++;k%=4;delay_ms(500);if(k==0){write_string(0,95,"SQ ");}else if(k==1){write_string(0,95,"Tri ");}else if(k==2){write_string(0,95,"Sin ");}else if(k==3){switch(m){case 0:write_string(0,95,"x1 ");break;case 1:write_string(0,95,"x10 ");break;case 2:write_string(0,95,"x100 ");break;case 3:write_string(0,95,"x1000 ");break;}}}if(y<2000){if(k==0){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, square[i]);i++;i %= NR_OF_SAMPLES;}else if(k==1){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, triangle[i]);i++;i%= NR_OF_SAMPLES;}else if(k==2){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, sine[i]);i++;i %= NR_OF_SAMPLES;}}else if((y>1999)&&(y<4500)){if(k==0){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, square[2*i]);i++;i %= 16;}else if(k==1){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, triangle[2*i]);i++;i%=16;}else if(k==2){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, sine[2*i]);i++;i %= 16;}}else if(y>4499){if(k==0){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, square[4*i]);i++;i %= 8;}else if(k==1){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, triangle[4*i]);i++;i%=8;}else if(k==2){dac_wait_for_channel_ready(&SPEAKER_DAC,SPEAKER_DAC_CHANNEL);dac_set_channel_value(&SPEAKER_DAC, SPEAKER_DAC_CHANNEL, sine[4*i]);i++;i %= 8;}}}}。