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CC2430F32RTC 参数 Datasheet PDF下载

CC2430F32RTC图片预览
型号: CC2430F32RTC
PDF下载: 下载PDF文件 查看货源
内容描述: 真正的系统级芯片解决方案的2.4 GHz IEEE 802.15.4 / ZigBee的 [A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee]
分类和应用: 电信集成电路
文件页数/大小: 212 页 / 1862 K
品牌: TAOS [ TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS ]
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CC2430  
Radio : Clear Channel Assessment  
therefore also provides an average correlation  
value for each incoming packet, based on the  
eight first symbols following the SFD. This  
unsigned 7-bit value, which should be as high  
as possible, can be looked upon as a  
indication of the “chip error rate,” although  
CC2430 does not perform chip decision.  
quality frame while a value of approx. 50 is  
typically the lowest quality frames detectable  
by CC2430.  
Software must convert the correlation value to  
the range 0-255 defined by [1], e.g. by  
calculating:  
LQI = (CORR – a) · b  
As described in the Frame check sequence  
section on page 162, the average correlation  
value for the eight first symbols is appended to  
each received frame together with the RSSI  
limited to the range 0-255, where a and b are  
found  
empirically  
based  
on  
PER  
measurements as a function of the correlation  
value.  
and  
CRC  
OK/not  
OK  
when  
MDMCTRL0L.AUTOCRC is set. A correlation  
value of approx. 110 indicates a maximum  
A combination of RSSI and correlation values  
may also be used to generate the LQI value.  
14.25 Clear Channel Assessment  
The clear channel assessment signal is based  
00 Reserved  
on the measured RSSI value and  
a
01 Clear channel when received energy  
is below threshold.  
programmable threshold. The clear channel  
assessment function is used to implement the  
CSMA-CA functionality specified in [1]. CCA is  
valid when the receiver has been enabled for  
at least 8 symbol periods.  
10 Clear channel when not receiving  
valid IEEE 802.15.4 data.  
11 Clear channel when energy is below  
threshold and not receiving valid  
IEEE 802.15.4 data  
Carrier sense threshold level is programmed  
by RSSI.CCA_THR. The threshold value can  
be programmed in steps of 1 dB. A CCA  
hysteresis can also be programmed in the  
MDMCTRL0H.CCA_HYSTcontrol bits.  
Clear channel assessment is available on the  
RFSTATUS.CCA  
RF  
register  
bit.  
RFSTATUS.CCAis active high. This register bit  
will also set the interrupt flag RFIF.IRQ_CCA.  
All three CCA modes specified by [1] are  
implemented in CC2430. These are set in  
MDMCTRL0L.CCA_MODE, as can be seen in  
the register description. The different modes  
are:  
Implementing CSMA-CA may easiest be done  
by using the STXONCCA command strobe  
given by the CSMA-CA/strobe processor, as  
shown in the Radio control state machine  
section on page 166. Transmission will then  
only start if the channel is clear. The  
TX_ACTIVE status bit in the RFSTATUS RF  
register may be used to detect the result of the  
CCA.  
14.26 Frequency and Channel Programming  
The operating frequency is set by  
programming the 10 bit frequency word  
automatically set by CC2430, so the frequency  
programming is equal for RX and TX.  
located  
FSCTRLL.FREQ[7:0].  
frequency FC in MHz is given by:  
in FSCTRLH.FREQ[9:8]  
and  
IEEE 802.15.4 specifies 16 channels within  
the 2.4 GHz band, numbered 11 through 26.  
The RF frequency of channel k is given by [1] :  
The  
operating  
FC = 2048 + FREQ[9:0]MHz  
FC = 2405 + 5 (k-11) MHz, k=11, 12, ..., 26  
where FREQ[9:0] is the value given by  
FSCTRLH.FREQ[9:8]:FSCTRLL.FREQ[7:0]  
For  
operation  
in  
channel  
k,  
the  
FSCTRLH.FREQ:FSCTRLL.FREQ  
register  
should therefore be set to:  
In receive mode the actual LO frequency is FC  
– 2 MHz, since a 2 MHz IF is used. Direct  
conversion is used for transmission, so here  
the LO frequency equals FC. The 2 MHz IF is  
FSCTRLH.FREQ:FSCTRLL.FREQ= 357 + 5 (k-11)  
14.27 VCO and PLL Self-Calibration  
CC2430 Data Sheet (rev. 2.1) SWRS036F  
Page 169 of 211