TI中文支持网
TI专业的中文技术问题咨询交流网站

ADS1115 Digital Comparator 单用 ALERT 功能,无反应

我只需要 ALERT 功能。 

Continous-conversion mode 下

COMP_MODE  :置0设置为Traditional mode;

COMP_POL  :置0 active low

COMP_LAT:置0 Non-latching comparator

COMP_QUE[1:0] :10 

设置阈值

LowThreshold = 1220

highThreshold = 1280

用直流源模拟输入:ADC 采样由1800-1000,ALERT 一直为低电平。并未出现手册中 Figure 28 图形

另外:我将Hi_thresh register MSB to 1 and the Lo_thresh register MSB to 0 。ALERT pin是有连续的波形产生的,说明电路,CPU和ads1115通信 正常。

我的需求就是,ADC采样值超出阈值后,ALERT pin有电平变化,请问如何配置?

user151383853:

The ALERT/RDY pin can also be configured as a conversion ready pin. Set the most-significant bit of the Hi_thresh register to 1 and the most-significant bit of Lo_thresh register to 0 to enable the pin as a conversion ready pin. The COMP_POL bit continues to function as expected. Set the COMP_QUE[1:0] bits to any 2-bit value other than 11 to keep the ALERT/RDY pin enabled, and allow the conversion ready signal to appear at the ALERT/RDY pin output. The COMP_MODE and COMP_LAT bits no longer control any function. When configured as a conversion ready pin, ALERT/RDY continues to require a pullup resistor. The ADS111x provide an approximately 8-µs conversion ready pulse on the ALERT/RDY pin at the end of each conversion in continuous-conversion mode, as shown in Figure 29. In single-shot mode, the ALERT/RDY pin asserts low at the end of a conversion if the COMP_POL bit is set to 0.

user6067219:

回复 user151383853:

我使用AIN0 ,作为输入源

配置如下:

1.Config 寄存机 high Byte 0x42 ,low Byte 0xF8;

 2.设置 阈值: LowThresholdValue 1800,HighThresholdValue2500

3. 输入ADC 检测值在 1200-3000变化,ALERT 引脚无变化。

请问如何设置, ALert才能得到下图波形

赞(0)
未经允许不得转载:TI中文支持网 » ADS1115 Digital Comparator 单用 ALERT 功能,无反应
分享到: 更多 (0)