在ADC采样时，需要对通道进行配置：
const ADC_INIT_CHANNEL_STRUCT adc_Direct_current =
{
ADC0_SOURCE_AD18,
ADC_CHANNEL_MEASURE_LOOP | ADC_CHANNEL_START_NOW, // runs continuously after IOCTL trigger
4, // number of samples in one run sequence
0, // time offset from trigger point in us
30, // period in us
0x10000, // scale range of result (not used now)
10, // circular buffer size (sample count)
MY_TRIGGER, // logical trigger ID that starts this ADC channel
#if MQX_USE_LWEVENTS
&evn,
0x01 // mask of event to be set
#endif
}
问题1：对于ADC_CHANNEL_START_NOW指令，在MQX的IO驱动手册ADC章节写的是：ADC_CHANNEL_START_NOW Measurement starts immediately after fopen(). initiating with the IOCTL_ADC_RUN_CHANNEL ioctl command. This flag is mutually exclusive with ADC_CHANNEL_START_TRIGGERED. 意思是fopen()后马上开始采样，通过ioct1指令启动。这两个不是矛盾了么？
问题2：在通道配置时有一个 circular buffer size (sample count) ，这里设置的是10，也就是说有这么大的空间来存储采样到的数据了？那如果一直采样，采得的数据超过10个会怎么放呢？是向队列一样覆盖前面的数据吗?
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发表于 2014-3-4 14:32:20
沉默卡
照妖镜
楼主
