[问答]

PIC24F MCP3201和MCP4921的SPI问题该怎么理解？

1454 SPI 代码

问答对人有帮助，内容完整，我也想知道答案0 大家好！我用PIC24F04KA200做吉他踏板。我用adc和dac mcp3201和mcp4921。有两个问题我不明白：1。如果另一个SPI模块被寻址，ADC MCP31不工作。现在，我在ADC和DAC中同时处理一个代码，作为一个工作。有没有人知道为什么在接收到CLK脉冲后，ADC没有响应，而MCP131的CS是1？我需要在什么地方加个电阻吗？2。直接到dac的Adc听起来像个比特破碎机，换言之，spi更新频率远远不够快。SPI设置是：读和写代码是：主要我做的是调用例程和将输入移动到输出。所以在MP3201的数据表中，它表示 50ksps@2.7V，并以3.3V运行。表格显示CLK也可以达到8000khz。MCP4921数据表声称支持20Mhz的时钟。那么我有机会让它工作得更快并且让其他spi设备像ram模块一样工作吗？谢谢你的帮助！问候，JP 以上来自于百度翻译以下为原文 Hello all! I'm working on a guitar pedal using a PIC24F04KA200. I use the adc and dac mcp3201 and mcp4921. There are two issues which I do not understand: 1. The adc mcp3201 does not work if another spi module is addressed. Right now I address both adc and dac in a single piece of code, as a work around. Does anyone know why the adc doesn't respond after receiving clk pulses while CS of mcp3201 is 1? do I need to add a resistor somewhere? 2. Adc directly to dac sounds like a bitcrusher, in other words the spi update frequency is nowhere near fast enough. SPI set tings are: void spi1_init(void) { SPI1CON1bits.PPRE = 2; SPI1CON1bits.SPRE = 1; SPI1CON1bits.MSTEN = 1; SPI1CON1bits.CKP = 0; SPI1CON1bits.SSEN = 0; SPI1CON1bits.CKE = 1; SPI1CON1bits.SMP = 0; SPI1CON1bits.MODE16 = 1; SPI1CON1bits.DISSDO = 0; SPI1CON1bits.DISSCK = 0; SPI1CON2 = 0x0000; SPI1STAT = 0x8000; LATAbits.LATA4 = 1; LATAbits.LATA6 = 1; LATBbits.LATB15 = 1; } Read and write code is: void Write_Guitar() // read and write, since mcp3201 behaves weird { LATBbits.LATB15 = 0; //cs LATAbits.LATA4 = 0; First_SPI_int = 0x3000 + Guitar_output; //write guitar data spi1_write(First_SPI_int); //places data in buffer, wait for SPITBF Guitar_input = ((spi1_read()<<2)>>3); //read from mcp3201 (+remove preceding dont care bits and make it 12 bit) delay(80); //additional delay for it to actually work LATBbits.LATB15 = 1; LATAbits.LATA4 = 1; } In main all I do is call routines and move input to output. So in the datasheet of MCP3201 it says 50ksps @ 2.7V and it runs at 3.3V. The PIC datasheet shows CLK can go up to 8000khz aswell. The MCP4921 datasheet claims 20Mhz clock support. So is there any chance I can get it to work faster and to have other spi devices working like the ram module? I appreciate your help! Regards, JP 0
2019-7-23 14:15:16　　评论淘帖0 邀请回答您可以邀请以下用户，快速回答问题 × qun333 该类别下有 57 个回答。邀请回答技术发广告该类别下有 56 个回答。邀请回答 caoguiqun 该类别下有 56 个回答。邀请回答 psw30 该类别下有 44 个回答。邀请回答伊丹姿子该类别下有 41 个回答。邀请回答 uwufwjrw 该类别下有 39 个回答。邀请回答 hetao1111 该类别下有 38 个回答。邀请回答 lc123617 该类别下有 35 个回答。邀请回答欧阳大大该类别下有 32 个回答。邀请回答作死不止该类别下有 31 个回答。邀请回答 asd010 该类别下有 31 个回答。邀请回答 60user92 该类别下有 29 个回答。邀请回答 wy8719 该类别下有 29 个回答。邀请回答 haikitty 该类别下有 28 个回答。邀请回答 ju978779 该类别下有 28 个回答。邀请回答嘻嘻爱哈哈该类别下有 28 个回答。邀请回答 xiuzhen122 该类别下有 27 个回答。邀请回答 pol666 该类别下有 27 个回答。邀请回答 ueywyrsdfs 该类别下有 26 个回答。邀请回答 lhly23 该类别下有 25 个回答。邀请回答举报张璨相关推荐 •PIC18F2331简单SPI和DAC（MCP4921）似乎缺少东西2161 • MicrochipPICSPI不兼容wrt slave select2204 • 请问如何使用SPI将MCP2941 DAC IC与PIC16f877a微控制器连接？1294 • 可以通过SPI向MCP2515 CAN总线监控演示板添加额外的器件吗？1228 •MCP2515通信问题3967 • MRF24J40的性能不好763 • 如何通过I2C将Pic18F8722与MCP23017接口的任何代码吗944 •MCP3911模拟通道采集电压2724 • 与PIC16F877A的CAN接口如何连接MCP2515？992 • 如何解决扩展CAN芯片MCP2515的驱动移植问题？1651 1个回答

答案对人有帮助，有参考价值0 您需要两个上拉10K，一个在MCP3201 CS上，另一个在MCP4921 CS上。您不能同时让两个芯片选择活动。选择一个设备，写/读，取消选择，选择另一个设备，写/读，取消选择。你要么将SPI时钟设置为最低频率的设备，要么变得复杂，在设备之间改变时钟。以上来自于百度翻译以下为原文 You need two pullups 10K, one on MCP3201 CS and the other on MCP4921 CS. you cannot have both chip selects active at the same time. Select one device, write/read, deselect, the select the other device, write/read, deselect. you either set the SPI clock to the lowest frequency device, or get complicated and change the clock between devices.

2019-7-23 14:28:07 评论举报李维嘉