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sn74lvc1t45dbvr

Other Parts Discussed in Thread: CC3200, SN74LVC1T45

sn74lvc1t45dbvr是什么总线收发芯片呀

  • 它不是什么总线收发芯片,而是一个用于总线或是信号线电平转换的芯片。

    具体的功能,可以在TI的官网上面查找datasheet。

    谢谢

  • 双电源电平转换器件,可以用与多种总线接口,解决电平不匹配问题

  • 您好,用cc3200开发板uart输出wifi信号强度,为啥用串口助手能看到16进制的强度值,但是用示波器放在 sn74lvc1t45dbvr4引脚上检测不到电平变化,一直都是3.3V呢?

  • 能不能把sn74lvc1t45的相关部分原理图附上来

  • CC3200的原理图和我用示波器检测时的照片都附上了,谢谢啦

  • 您可以电话联系我吗?很着急的问题,还是学生,请赐教呀。13520001544

  • 是不是因为

    static long WlanScan(void *pvParameters)
    {
      
        long lRetVal = -1;

        unsigned short ucIndex;
        unsigned char ucpolicyOpt;
        union
        {
            unsigned char ucPolicy[4];
            unsigned int uiPolicyLen;
        }policyVal;
       
        InitializeAppVariables();

        //
        // Following function configure the device to default state by cleaning
        // the persistent settings stored in NVMEM (viz. connection profiles &
        // policies, power policy etc)
        //
        // Applications may choose to skip this step if the developer is sure
        // that the device is in its default state at start of applicaton
        //
        // Note that all profiles and persistent settings that were done on the
        // device will be lost
        //
        lRetVal = ConfigureSimpleLinkToDefaultState();
        if(lRetVal < 0)
        {
            if (DEVICE_NOT_IN_STATION_MODE == lRetVal)
            {
                UART_PRINT("Failed to configure the device in its default state\n\r");
            }
            return lRetVal;
        }

        //UART_PRINT("Device is configured in default state \n\r");

        //
        // Assumption is that the device is configured in station mode already
        // and it is in its default state
        //
        lRetVal = sl_Start(0, 0, 0);
        if (lRetVal < 0 || ROLE_STA != lRetVal)
        {
            UART_PRINT("Failed to start the device \n\r");
            return lRetVal;
        }

        //UART_PRINT("Device started as STATION \n\r");

        //
        // make sure the connection policy is not set (so no scan is run in the
        // background)
        //
        ucpolicyOpt = SL_CONNECTION_POLICY(0, 0, 0, 0,0);
        lRetVal = sl_WlanPolicySet(SL_POLICY_CONNECTION , ucpolicyOpt, NULL, 0);
        if(lRetVal != 0)
        {
            GPIO_IF_LedOn(MCU_EXECUTE_FAIL_IND);
            UART_PRINT("Unable to clear the Connection Policy\n\r");
            return lRetVal;
        }
       
        //
        // enable scan
        //
        ucpolicyOpt = SL_SCAN_POLICY(1);
        //
        // set scan cycle to 10 seconds
        //
        policyVal.uiPolicyLen = 10;
        //
        // set scan policy - this starts the scan
        //
        lRetVal = sl_WlanPolicySet(SL_POLICY_SCAN , ucpolicyOpt,
                                   (unsigned char*)(policyVal.ucPolicy), sizeof(policyVal));
        if(lRetVal!=0)
        {
            GPIO_IF_LedOn(MCU_EXECUTE_FAIL_IND);
            UART_PRINT("Unable to set the Scan Policy\n\r");
            return lRetVal;
        }
        MAP_UtilsDelay(8000000);
        //
        // get scan results - all 20 entries in one transaction
        //
        ucIndex = 0;
        //
        // retVal indicates the valid number of entries
        // The scan results are occupied in netEntries[]
        //
        lRetVal = sl_WlanGetNetworkList(ucIndex, (unsigned char)WLAN_SCAN_COUNT,
                                        &netEntries[ucIndex]);
        if(lRetVal==0)
        {
            GPIO_IF_LedOn(MCU_EXECUTE_FAIL_IND);
            UART_PRINT("Unable to retreive the network list\n\r");
            return lRetVal;
        }
        /* put a break point here and check netEntries[] value for scan ssid list */
        //
        // get scan results - 4 transactions of 5 entries
        //
        ucIndex = 0;
        memset(netEntries, 0, sizeof(netEntries));

        do
        {
            lRetVal = sl_WlanGetNetworkList(ucIndex,
                                            (unsigned char)WLAN_SCAN_COUNT/4,
                                            &netEntries[ucIndex]);
            ucIndex += lRetVal;
        }
        while ((lRetVal == WLAN_SCAN_COUNT/4) && (ucIndex < WLAN_SCAN_COUNT));
        /* put a break point here and check netEntries[] value for scan ssid list */
        //
        // disable scan
        //
        ucpolicyOpt = SL_SCAN_POLICY(0);
        lRetVal = sl_WlanPolicySet(SL_POLICY_SCAN , ucpolicyOpt, NULL, 0);
        if(lRetVal != 0)
        {
            GPIO_IF_LedOn(MCU_EXECUTE_FAIL_IND);
            UART_PRINT("Unable to Clear the Scan Policy\n\r");
            return lRetVal;
        }


        //UART_PRINT("SUCCESS\n\r");

        return SUCCESS;
    }

    这个扫描WIFI信号的函数速度太慢了,11秒扫描一次,所以示波器显示不出来?怎么提高这个的扫描速度呢?

    求解呀大神

  • 原理图部分没有问题,你的意思是串口输出到调试助手上有信号,但是用示波器看不到信号?串口连电脑时你接的引脚和你用示波器测试的引脚都是哪些引脚啊?或者你使用USB板子上接口看的串口数据?

  • 就是你说的那样,示波器上没有显示数据,但用USB连电脑,在串口助手上能接受到数据,是因为传输速度太慢吧?还有我买的就是ti的cc3200开发板呀,你用过吗?电话联系可以吗?太慢了这样,也说不太清楚

  • 我没用过这个板子,我是负责接口相关的,对无线产品不太了解。但是你说的这种情况不太可能啊,输出有数据,示波器怎么会看不到数据呢?这跟速度没有关系啊,串口有数据,说明SN74LVC1T45向串口转USB的那片IC传了数据,说明引脚上肯定是有电平波动的数据的啊,你确定示波器没有问题的吗