CC2420-RTR1 datasheet(41/92 Pages) TI

41 / 92 page

CC2420

SWRS041B

Page 41 of 89

18 Address Recognition

CC2420 includes hardware support for

address recognition, as specified in [1].

Hardware address recognition may be

enabled

disabled

using

the

MDMCTRL0.ADR_DECODE

control bit.

Address recognition is based on the

following requirements, listed from section

7.5.6.2 in [1]:

•

The frame type subfield shall not

contain an illegal frame type

•

If the frame type indicates that the

frame is a beacon frame, the

source PAN identifier shall match

macPANId unless macPANId is

equal to 0xFFFF, in which case

the

beacon

frame

shall

accepted regardless of the source

PAN identifier.

•

If a destination PAN identifier is

included in the frame, it shall

match macPANId or shall be the

broadcast

PAN

identifier

(0xFFFF).

•

If a short destination address is

included in the frame, it shall

match either macShortAddress or

the broadcast address (0xFFFF).

Otherwise

extended

destination address is included in

the

frame,

shall

match

aExtendedAddress.

•

If only source addressing fields

are included in a data or MAC

command frame, the frame shall

only be accepted if the device is a

PAN coordinator and the source

PAN

identifier

matches

macPANId.

If any of the above requirements are not

satisfied and address recognition is

enabled,

CC2420 will disregard the

incoming frame and flush the data from

the RXFIFO. Only data from the rejected

frame is flushed, data from previously

accepted frames may still be in the

RXFIFO.

The IOCFG0.BCN_ACCEPT control bit

must be set when the PAN identifier

programmed into

CC2420 RAM is equal to

0xFFFF and cleared otherwise. This

particularly applies to active and passive

scans as defined by [1], which requires all

received beacons to be processed by the

MAC sublayer.

Incoming frames with reserved frame

types (FCF frame type subfield is 4, 5, 6 or

however

accepted

the

RESERVED_FRAME_MODE

control bit in

MDMCTRL0

is set. In this case, no further

address recognition is performed on these

frames. This option is included for future

expansions

the

IEEE

802.15.4

standard.

If a frame is rejected,

CC2420 will only start

searching for a new frame after the

rejected frame has been completely

received (as defined by the length field) to

avoid detecting false SFDs within the

frame.

The

MDMCTRL0.PAN_COORDINATOR

control bit must be correctly set, since

parts of the address recognition procedure

requires knowledge about whether the

current device is a PAN coordinator or not.

19 Acknowledge Frames

CC2420 includes hardware support for

transmitting

acknowledge

frames,

specified in [1]. Figure 23 shows the

format of the acknowledge frame.

If MDMCTRL0.AUTOACK is enabled, an

acknowledge frame is transmitted for all

incoming frames accepted by the address

recognition with the acknowledge request

flag set and a valid CRC. AUTOACK

therefore does not make sense unless

also ADR_DECODE and AUTOCRC

are

enabled. The sequence number is copied

from the incoming frame.

CC2420-RTR1 数据表(PDF) 41 Page - Texas Instruments

CC2420-RTR1 数据表(HTML) 41 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

数据表下载