mrf24j40 Microchip Technology Inc., mrf24j40 Datasheet - Page 11

• Manufacturer Part Number: mrf24j40
• Description: Ieee 802.15.4? 2.4 Ghz Rf Transceiver
• Manufacturer: Microchip Technology Inc.

3.0
All memory in the MRF24J40 is implemented as static
RAM. There are five types of memory in the
MRF24J40:
• Short Address Control Registers
• Long Address Control Registers
• Transmit Buffers
• Receive Buffers
• Security Buffer
The control registers, both long and short, are used for
configuration, control, and status retrieval of the
MRF24J40. The control registers are directly read and
written to by the SPI interface. The transmit and receive
buffers contain transmit and receive memory used by
the controller to transmit and receive data.
FIGURE 3-1:
© 2006 Microchip Technology Inc.
MEMORY ORGANIZATION
MRF24J40 MEMORY SPACE
3Fh
00h
Control Registers
Short Address
Short Address
Space
Advance Information
Transmit
Buffers
Control
Registers
Security
Receive
FIFO
The security buffer provides an engine for the
MRF24J40 MAC, which is compatible with the
IEEE 802.15.4 LR-WPAN (ZigBee). The security buffer
contains the following features:
• Transmit encryption and receive decryption.
• Seven-mode security suite.
• 64 x 8-bit security RAM for security suite storing;
• Security of APL and NWK layers can be achieved
The SPI interface used to write and read these regis-
ters is described in Section 4.0 “Serial Peripheral
Interface (SPI)”.
Figure 3-1 shows the data memory organization for the
MRF24J40.
one receive key and three transmit keys for TX
FIFOs. Beacon FIFO and GTS2 FIFO share the
same key space since they will not conflict with
each other. Normal FIFO and GTS1 FIFO both
have their own transmit key.
using the same engine. The upper layer security
function is compliant to the ZigBee V1.0 and
ZigBee 2006 specifications.
2BEh
0FFh
1FFh
2BFh
2FFh
07Fh
17Fh
27Fh
38Fh
000h
080h
100h
180h
200h
280h
300h
Control Registers
Long Address
Unimplemented
Security Buffer
Long Address
GTS1 FIFO
GTS2 FIFO
TXN FIFO
TXB FIFO
RX FIFO
Space
MRF24J40
DS39776A-page 9