|
|
//发送一条delayed 信息(定时发送)
//定时发送的好处是可以将 这条信息发送的具体时间 打包到这个数据包发送给对方
final_tx_time = dwt_readsystimestamphi32() + 0x17cdc00/80;//10ms/8
我想知道0x17cdc00/80是如何计算选取的？
此外，我对于DW1000 User Manual中介绍有关时间基准的问题不理解，希望各位能够解惑。
在Clock Periods and Frequencies
The chipping rate given by the IEEE 802.15.4-2011 standard [1] is 499.2 MHz. DW1000 system clocks are referenced to this frequency. Where the system clock frequency is given as 125 MHz, this is an
approximation to the actual system clock frequency of 124.8 MHz. Similarly, where the system clock period is given as 8 ns, this is an approximation to the actual period of 1/ (124.8×106) seconds
在Register file: 0x06 – System Time Counter中
System time and time stamps are designed to be based on the time units which are nominally at 64 GHz, or more precisely 499.2 MHz × 128 which is 63.8976 GHz. In line with this when the DW1000 is in idle mode with the digital PLL enabled, the System Time Counter is incremented at a rate of 125 MHz in units of 512. The nine low-order bits of this register are thus always zero. The counter wrap period of the clock is then: 240 ÷ (128×499.2e6) = 17.2074 seconds.
在上述中写道系统时钟频率是124.8MHz，那么64GHz又是用来干什么的？还有其中出现的数字128，512等数字，不理解具体是用来干嘛的。
|
|
发表于 2021-12-18 20:58:01
收藏
发表于 2021-12-19 19:44:05
楼主
