CC2520_11 Datasheet, PDF (43/133 Pages) Texas Instruments – 2.4 GHZ IEEE 802.15.4/ZIGBEE RF TRANSCEIVER

CC2520 DATASHEET
2.4 GHZ IEEE 802.15.4/ZIGBEE® RF TRANSCEIVER
SWRS068 – DECEMBER 2007
13 Instruction Set
The CC2520 has a comprehensive instruction set. The instructions are transferred to CC2520 via the SPI,
and can consist of one or more bytes. The first byte contains the unique op-code and the following bytes are
parameters needed to execute the selected instruction. In the following sections, every instruction and
parameter is described in detail.
13.1 Definitions
• All parameters and data are transferred over the SPI with their most significant bit first and their
least significant bit last.
• For instructions that read data from CC2520, the data byte will replace the status byte on the SO
pin.
• Address parameters point to the least significant byte in a block of data. The address A+1 contains
the next but least significant byte and so on.
• When CC2520 automatically increments addresses, it will wrap around when incrementing beyond
the highest possible address (0xFFF).
• An instruction is ended by either sending the complete instruction (for finite instructions) or raising
CSn (For infinite instructions, indicated by “...” in the instructions summary).
• Once an instruction is ended a new instruction can be started.
• If an instruction is ended before it is complete or if the instruction is not recognized, an
OPERAND_ERROR exception is raised.
• If the user sets parameter bits explicitly marked as ‘0’ in instruction summary table to ‘1’ an
OPERAND_ERROR exception is raised.
• When an instruction is aborted an error exception is raised and the SPI interface ceases to receive
further data until CSn has been set high then low again. The instruction that was aborted may have
made changes to memory contents before it was aborted.
• If the SPI interface is reset (by pulling CSn high) in the middle of an SPI byte transfer (i.e. not
between bytes) an SPI_ERROR exception is raised.
13.2 Instruction Descriptions
The codes shown below are used in the descriptions of the instructions. They represent bits selectable by
the user. A sequence of bits thus represented by the same letter, even when spanning multiple bytes
represents a word with a width equal to the number of repeated letters and with MSB the leftmost bit in the
first byte transferred with this encoding. Such words may be represented in the text as a capital letter of the
encoding letter in which case they shall be interpreted as a positive integer encoded by the bits represented
in the encoding by the same letter only in lower-case.
Note that the bits that refer to one such integer need not be continuous in the encoding. So the encoding
aaaaeeee aaaaaaaa eeeeeeee represents two 12 bit words transferred in three bytes with the most
significant bits of each word transferred in the first byte.
Table 11: Codes used in instruction set description
Code
a, e, k, n
b
i
d
s
p
m
c, f
-
Description
Address data
Bit address
Instruction
Data
Status byte
Priority
Security parameter
Count
Don’t care
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