MRF24XA_15 Datasheet, PDF (96/258 Pages) Microchip Technology – Low-Power, 2.4 GHz ISM-Band IEEE 802.15.4™ RF

MRF24XA
Buffer 1 holds the processed (encrypted, FCS-
appended) frame. If RXBUF1PP is set, frame filtering is
performed and RXIF interrupt is generated.
Alternatively, the processing is performed in Buffer 2
(the normal receive buffer) using TXBUF2PP and
RXBUF2PP. Note that unlike TXBUF1PP and
TXBUF2PP, RXBUF1PP and RXBUF2PP do not
automatically clears when RXIF is set but selects which
buffer must be processed when RXDEC is issued.
FIGURE 4-5:
IN-PLACE TEST USING A SINGLE NODE: EXAMPLE SCENARIO (MESSAGE
SEQUENCE CHART)
Node in Originator Role
Same Node in Recipient Role
TX Host
MCU
SPI, INTn
1
TX Configuration
(AUTOACKEN=1)
2 payload
TX
Device
RX
Device
AUTOACKEN is ’Don’t Care’
SPI, INTn
RX Host
MCU
4
MHR
(SecEn=1)
(AckReq=1)
5
Load buffer
AckReq is ’Don’t Care’
6
Wait for
confirmation
interrupt
Security Key
TXBUF1PP 1
7
Get AckReq, SecEn
Encrypt
FCS Append
Encrypted frame in TX buffer
16
Confirmation
done
TXIF
(Interrupt Serviced)
8
15
13
Change Role
Process TX buffer as if
frame was received
9 FCS Check
(Accepted)
10
14
RX Configuration
(AUTOACKEN=x)
RXEN 1
RXBUF1PP 1
?
RXIF
Read MHR
RXEC, Security Key
1
3
Wait for
RXIF
interrupt
11
12
SecEn=1
Decrypt
Decryption
complete
17
RXDECIF
Buffer unlocked
Wait for new frame
Read Payload
RXBUFFULL 0
Wait for
RXDEC
interrupt
Interrupt
Serviced
18
Free the buffer
Wait for
new frame
DS70005023C-page 96
Preliminary
 2015 Microchip Technology Inc.