ADS1298的常见问题

 

问: I want to use the ADS1298ECGFE EVM without the MMB0, is this possible?

答: Yes!  Absolutely!  There are a few things you need to consider first:

• Board Power

The power for the ADS1298ECGFE board is delivered through J4; a 10-pin 2 row female socket.  By way of the MMB0 connector J5;  +5V, +3.3V and +1.8V is delivered to the ADS1298 board.  The +5V supply goes through regulators which provide the analog voltage to the ADS1298 chip.  The analog rails are either 0V and +3.3 or +/-2.5V depending on JP2 and JP24.  The digital rail of the ADS1298 is configured via JP28.  You can choose to use the 3.3V source (short JP28 pins 2-3) or the 1.8V source (short JP28 pins 1-2).  The actual applied voltage does not need to be connected to J4 directly, it can be applied to test points TP7 (the +5V), TP9 (+1.8V) and TP10 (+3.3V).  Ground is available through TP1, TP8, TP11; J4 pins 5 and 6; and J3 pins 4, 10 and 18. 

• SPI Interface

The SPI communication requires a minimum 3-wire interface with SCLK, SOMI and SIMO.  The ADS1298 is a SLAVE device and is not capable of generating a serial clock.  The SCLK line is on J3 pin 4.  SIMO and SOMI are located on J3 pins 11 and 13 respectively.  The SCLK should dwell low, with valid data on the falling clock edge.  This is most often considered to be SPI mode 1.

 

 

 

问: Where are the Gerber files for the ADS1298ECGFE-PDK Boards?

答: Here are the Gerber files for the ADS1298ECGFE-PDK, the ADS1298RECGFE-PDK and the ADS1198/1298ECGFE-PDK in TQFP packages.

 

• ADS1298ECGFE-PDK Rev A  - BGA Version
• ADS1198/1298ECGFE-PDK Rev C - TQFP Version
• ADS1298RECGFE-PDK Rev B  - BGA Only 

 

 

 

问: What do I do with the DRDY output?  My processor does not have a DRDY input so I'm not sure where to connect this signal.

答:  The DRDY output of the ADS1298 is intended to act as an interrupt to your host processor.  Most micro controllers or digital signal processors have the ability to be 'interrupted' while performing comuptations by an external peripheral - like the ADS1298 connected to an SPI port.  The code developer would then put something into an interrupt service routine (ISR) that, when ready, the controller would perform the task associated with the ISR.  For the ADS1298, that might be to go read eight channels worth of data along with the status byte - 9*24-bits of information to store and process.

 

 

 

问:  What is the purpose of the MSP430G2121` on the ADS1298RECGFE-PDK?

答: The MSP430G2121 on the ADS1298RECGFE-PDK board is there to help simulate respirations. It is factory programmed (through J7) to create a square wave of 0.1 to 0.5Hz. The frequency is selectable in the GUI as 0.1, 0.2, 0.3 (default), 0.4 or 0.5Hz. That signal is fed through JP36 to a comparator (U12 pin 2) and the output of the comparator drive the analog switch (U11). If you want to use your own signal generator to simulate respiration, you can apply a square wave to the SMA connector (J6) and move the shunt on JP36 to cover pins 2-3.

The MSP430 is there only to help you evaluate the respiration function without having to connect additional test gear to the EVM. You do not need to put anything from your processor into J7. J7 is there to accommodate the Spy-Bi-Wire Interface of the MSP430G2121 only, which is how we programmed the device to generate the square wave mentioned above.

 

 

问:  What is the purpose of the EEPROM on the ADS1298 and what data does it contain?

答:  The EEPROM located at U16, just south of J3 on the ADS1298ECGFE board contains data pertinent to the assembly level of the board.  It contains a unique part number for the assembly as well as the assembly revision of the board.  There is nothing in the EEPROM that the end user need to be concerned with - the ADS1298ECGFE-PDK software does not interrogate the EEPROM and it contains no 'boot data' needed to run the GUI.

 

 

 

问: What do I do with the DRDY output?  My processor does not have a DRDY input so I'm not sure where to connect this signal.

答:  The DRDY output of the ADS1298 is intended to act as an interrupt to your host processor.  Most micro controllers or digital signal processors have the ability to be 'interrupted' while performing comuptations by an external peripheral - like the ADS1298 connected to an SPI port.  The code developer would then put something into an interrupt service routine (ISR) that, when ready, the controller would perform the task associated with the ISR.  For the ADS1298, that might be to go read eight channels worth of data along with the status byte - 9*24-bits of information to store and process.

 

 

 

问: What is the maximum SCLK speed that I can apply to the ADS1298?

答:The maximum SCLK speed depends on the applied DVdd voltage.  For DVdd between 2.7 and 3.6VDC, the fastest SCLK you can is is 20MHz (50ns period).  Below 2.7V, the SCLK is limited to a period of 66.6ns or approximately 15MHz. 

 

 

问: What's the difference between ADS1298/ADS1298R?

答: The main difference between the ADS1298 and ADS1298R is that the ADS1298R has integrated respiration impedance measurement functionality associated with CH1 (see the note at the top of page 9 in the data sheet).  Other than that, they are the same.   For more details on how the function works, please feel free to review this application note:

Respiration Rate Measurement Using Impedance Pneumography 

The ADS1298R will not be offered in the TQFP package, it will only be available in the BGA version.

 

 

问. I just received my ADS1298ECGFE-PDK and get a constant error message "Download failed..reset the hardware".  What can be wrong?

答. The message is caused when the PC does not see the MMB0.  It should also be followed up by a dialog box that pops up with a message "The firmware load has failed due to a timeout condition.  Please reset the hardware to continue loading the firmware."  Let's first address the potential hardware issues:

To debug the MMB0 hardware, there are a couple of things to look for, first is a shunt jumper on J12 which is a two pin jumper just below and slightly left of the power jack on the MMB0.  If this shunt came off through the shipping process for some reason, you would get the error message you describe.  The second possibility is that the MMB0 is not configured for USB Boot Mode.  If you have the REV C version of the MMB0 (REV C has four standoffs mounted on the bottom of the board, REV D has four rubber 'stick-on' feet) there is a switch just to the right of the power jack.  This switch needs to be in the USB position (towards the center of the board) for the firmware to properly load.  The REV D version of the board does not have this switch installed, the USB boot mode is set by virtue of a wired short on S4.  The final possibility is the actual RESET switch.  The RESET switch (S3) is in the upper right corner of the MMB0 - while rare, we have had a few of these switches fail short on the REV C boards.  If you do not 'feel' the switch give under the pressure of a press with your finger, verify the switch reads 'open' or infinite resistance using a multi-meter between the two outside pins in the upper right corner of the board. 

If J12, S4 and S3 are configured properly, the next item to look for is that the drivers for the MMB0 are actually getting loaded on your PC.  After installing the software and powering up the board for the first time, with the USB cable plugged in, you should get the 'Found New Hardware' prompt.  The first driver that gets installed is the NI-VISA USB Device Driver.  Select the 'No, not this time' and 'Install the software automatically' options when prompted.  After installing the device driver, the device manager should show a NI-VISA USB Devices type with TMS320VC5509A (NI-VISA) driver.  From here, once you start the ADS1298 software for the first time, you should get another prompt regarding the finding of a new device.  The second driver is the USBStyx Driver, again follow the prompts as above (don't search, automatically install) and let the installation finish.  During this period, the firmware may timeout and give you the "Download failed..reset the hardware", but pressing the reset button at this point or re-starting the ADS1298ECG-FE GUI should clear that message.

 

 

 ADS1298 的文档资料: http://e2e.ti.com/support/data_converters/precision_data_converters/m/videos__files/default.aspx 

 

 

 

 

ADS1298 的常见问题

1、 问：我想使用不带 MMB0 的 ADS1298ECGFE EVM，这是否可能？

答：是的，完全没问题！不过应首先考虑到以下几个方面：

- 电路板电源

ADS1298ECGFE 板的电源来自 10 引脚双排插座 J4。通过 MMB0 连接头 J5，可将 +5V、+3.3V 以及 +1.8V 交付给 ADS1298 板。+5V 供电电压通过稳压器，可为 ADS1298 芯片提供模拟电压。模拟电压轨既可以是 0V 和 +3.3，也可以是 +/-2.5V，具体情况取决于 JP2 和 JP24。可通过 JP28 对 ADS1298 的数字电压轨进行配置。您既能够选择采用 3.3V 供电电源（短 JP28 引脚 2-3），也可以选择 1.8V 供电电压（短 JP28 引脚 1-2）。实际施加的电压不需要直接连接 J4，可施加测试点 TP7（+5V）、TP9（+1.8V）以及 TP10（+3.3V）。接地通过 TP1、TP8、TP11 提供，J4 引脚 5 和 6 以及 J3 引脚 4、10 和 18。

- SPI 接口

SPI 通信需要 SCLK、SOMI 和 SIMO 最少三线接口。ADS1298 属于从系统 (SLAVE) 器件，不能生成串行时钟。SCLK 线路在 J3 引脚 4 上。SIMO 与 SOMI 分别位于 J3 引脚 11 和 13 上。SCLK 应为低，有效数据在下降时钟沿上。这通常被视为 SPI 模式 1。

2、问：ADS1298ECGFE-PDK 板的光绘文件在哪里？

答：以下为采用 TQFP 封装的 ADS1298ECGFE-PDK、ADS1298RECGFE-PDK 以及 ADS1198/1298ECGFE-PDK 的光绘 (Gerber) 文件。

- ADS1298ECGFE-PDK Rev A - BGA 版本

- ADS1198/1298ECGFE-PDK Rev C–TQFP 版本

- ADS1298RECGFE-PDK Rev B – 只有 BGA 版本

3、问：DRDY 输出该如何处理？我的处理器没有 DRDY 输入，因而我不确定该信号应连接到什么地方。

答：ADS1298 的 DRDY 输出旨在作为主机处理器的中断发挥作用。大多数微控制器或数字信号处理器都能在执行外部外设（如 ADS1298 连接到 SPI 端口）计算时提供“中断”功能。代码开发人员可在中断服务例程 (ISR) 中放入一些内容，在控制器进行 ISR 相关任务时准备就绪。对于 ADS1298 来说，可读取相当于 8 个通道的数据和状态字节，也就是存储和处理 9*24 位信息。

4、问：在 ADS1298RECGFE-PDK 上，MSP430G2121 的目的是什么？

答：ADS1298RECGFE-PDK 板上的 MSP430G2121 可对呼吸进行仿真。其通过工厂编程（通过J7）产生 0.1 到 0.5Hz 的方波。频率在 GUI 中可选为 0.1、0.2、0.3（默认）、0.4 或 0.5Hz。该信号通过 JP36 馈送至比较器（U12 引脚 2），而比较器输出则驱动模拟开关 (U11)。如果希望使用自己的信号生成器对呼吸进行仿真，则可向 SMA 连接头 (J6) 施加方波，并将 JP36 上的旁路转移覆盖引脚 2-3。

MSP430 的目的仅限于评估呼吸功能，而不必连接额外的 EVM 测试设备。处理器的任何元素都不必置入 J7。J7 的目的是协助 MSP430G2121 的双线 JTAG (Spy-Bi-Wire) 接口，这也是我们对器件编程并生成上述方波的方法。

5、问：ADS1298 上的 EEPROM 有何作用？它包含哪些数据？

答：ADS1298ECGFE 板上 J3 以南 U16 上的 EEPROM 包含电路板的汇编级相关数据。其包含唯一的汇编部件号和电路板的汇编修订号。最终用户不用担心 EEPROM 中的任何事项，ADS1298ECGFE-PDK 软件不会询问 EEPROM，而且其也不包含运行 GUI 所需的“启动数据”。

6、问：DRDY 输出该如何处理？我的处理器没有 DRDY 输入，因而我不确定该信号应连接到什么地方。

答：ADS1298 的 DRDY 输出旨在作为主机处理器的中断发挥作用。大多数微控制器或数字信号处理器都能在执行外部外设（如 ADS1298 连接到 SPI 端口）计算时提供“中断”功能。代码开发人员可在 ISR 中置入一些内容，在控制器进行 ISR 相关任务时准备就绪。对于 ADS1298 来说，可读取相当于 8 个通道的数据和状态字节，也就是存储和处理 9*24 位信息。

7、问：ADS1298 可用的最高 SCLK 速度是多少？

答：最高的 SCLK 速度取决于所施加的 DVdd 电压。如 DVdd 在 2.7 和 3.6VDC 之间，则最快速 SCLK 为 20MHz（50ns 周期）；如 DVdd 低于 2.7V，则 SCLK 限于 66.6ns 周期，频率约 15MHz。

8、问：ADS1298/ADS1298R 有什么区别？

答：ADS1298 与 ADS1298R 的主要区别在于 ADS1298R 集成了与 CH1 相关的呼吸阻抗测量功能（参见本产品说明书第 9 页顶部信息）。此外二者一致。如欲了解有关功能如何工作的细节，请参见应用手册：

使用阻抗充气造影术进行呼吸测量

ADS1298R 不提供采用 TQFP 封装的版本，仅提供 BGA 版。

9、问：我刚拿到 ADS1298ECGFE-PDK，但总遇到故障消息“下载失败……复位硬件”。这是什么原因？

答：该消息出现是因为 PC 没有发现 MMB0，另外，随后还会弹出对话框“固件加载因超时失败。请复位硬件并继续加载固件。”我们首先来解决潜在的硬件问题：

如欲调试 MMB0 硬件，需要注意几件事。首先是 J12 上的分流跳线 (shunt jumper)，其是一根双引脚跳线，刚好在 MMBO上电源插孔以下的略偏左处。如果由于某种原因分流跳线在运输过程中断开了，则会遇到上述报错消息。第二种可能性是未将 MMB0 配置为 USB 启动模式。如果您的 MMBO 为 REV C 版本（REV C 在电路板的底部安装了 4 个支架，而 REV D 则采用 4 个橡胶粘贴支脚），电源插孔右侧有一个开关。该开关应当处于 USB 位置（靠近电路板的中心），才能正确加载固件。电路板的 REV D 版本没有安装这个开关，通过 S4 上的连线短接设置 USB 启动模式。最后一种可能性就是实际的重设 (RESET) 开关。RESET 开关 (S3) 在 MMBO 的右上角，在极少见的情况下，可能会出现 REV C 板开关不能短接的问题。如果手指按压感觉不到开关，请在电路板右上角的两个外部引脚之间使用万用表验证开关是否为“开”或电阻值为无穷大。

若正确配置 J12、S4 和 S3，那么接下来就应检查在您的 PC 上是否正在载入 MMBO 的驱动器。安装完软件、插上 USB 线缆，首次上电启动电路板时，您应该会看到“发现新硬件 (Found New Hardware)”提示信息。第一个要安装的驱动器是 NI-VISA USB 器件驱动器 (NI-VISA USB Device Driver)。看到提示后选择“否，这次不”和“自动安装软件”。安装完器件驱动器后，器件管理器会显示带 TMS320VC5509A（NI-VISA）驱动器的 NI-VISA USB 器件类型。这时，一旦您首次启动 ADS1298 软件，就会获得发现新器件的另一个提示消息。第二个要安装的驱动器为 USBStyx 驱动器，仍然如上所述按照提示进行操作（不要搜索，选择自动安装），然后等待安装完成。在此期间，固件可能会超时并提示“下载失败……复位硬件”，不过这时我们可按下复位按钮或重启 ADS1298ECG-FE GUI，即可消除此信息。

以上的翻译若有啥建议，欢迎各位随时提出，以便我学习改进哟 :)

我想知道如何购买 ADS1298ECGFE这块评估板？如果我通过TI estore在线购买这块开发板，是否还需要支付额外的关税等费用？费用有多少呢？

购买者需要7%关税＋17%的增值税。

举个例子，若一块开发板eStore标价$200，进口报关，加上增值税，一共要支付　200*1.07*1.17 = $250.38 ≈ ¥1602.43。 $200在eStore上支付给TI；$50税金由报关的快递公司向购买者收取。

以下为TI官网相关条文： http://www.ti.com/corp/docs/legal/termsofuse_estore.shtml

你好，我看了ADC128D818的硬件手册，一个细节令我很困惑。P16页Figure6的时序图上写的是Internal Address Register Set Only，但是我翻遍全册，并没有找到这个内部地址寄存器的说明。这个寄存器到底存不存在？

To: Yuan Zhou

麻烦您再单发一个贴子, 这样让工程师更容易看到, 尽快帮您解决问题.谢谢!

我发了帖子，但是没有人回。很急

佩服

厉害呀。。。

我想问一下，我用的ADS1292R，读寄存器的状态位，前八位是对的，后4位是错误的，这是为什么？

我在安装ADS1298FE评估软件的时候遇到了问题，软件不支持windows系统的版本（试过xp sp2,sp3, win7），打开软件时会有LIBUSB0.DLL文件缺失的弹窗，添加修复之后，软件无法找到硬件。请问，这个软件适合的操作系统版本，一定是要xp sp2 32位（这个版本我也试过了，还是蹦弹窗提示，不好用）？labview run time engine, .net framework 4都有安装调试过

你好，你的问题解决了嘛，我安装评估软件也有这方面问题，添加修复之后，就出现了labview：未找到资源，我已经安装过labview run-time engine, .net framework 4 了。