CC2430 Datasheet, PDF (155/212 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
Radio : Command strobes
T_C
I-phase ¹
0
1
0
1
0
0
1
0
0
0
1
0
1
1
1
Q-phase
1
1
0
1
1
0
0
1
1
1
0
0
0
0
1
0
2T_C
Figure 34: I / Q Phases when transmitting a zero-symbol chip sequence, T_C = 0.5 µs
14.2 Command strobes
The CPU uses a set of command strobes to
control operation of the radio in CC2430.
Command strobes may be viewed as single
byte instructions which each control some
function of the radio. These command strobes
must be used to enable the frequency
synthesizer, enable receive mode, enable
transmit mode and other functions.
A total of nine command strobes are defined
for the radio and these can be written
14.3 RF Registers
The operation of the radio is configured
through a set of RF registers. These RF
registers are mapped to XDATA memory
space as shown in Figure 7 on page 31.
The RF registers also provide status
information from the radio.
individually to the radio or they can be given in
a sequence together with a set of dedicated
software instructions making up a simple
program. All command strobes from the CPU
to the radio pass through the CSMA-
CA/Command Strobe Processor (CSP).
Detailed description about the CSP and how
command strobes are used is given in section
14.34 on page 176.
The RF registers control/status bits are
referred to where appropriate in the following
sections while section 14.35 on page 183
gives a full description of all RF registers.
14.4 Interrupts
The radio is associated with two interrupt
vectors on the CPU. These are the RFERR
interrupt (interrupt 0) and the RF interrupt
(interrupt 12) with the following functions
• RFERR : TXFIFO underflow, RXFIFO
overflow
• RF : all other RF interrupts given by RFIF
interrupt flags
The RF interrupt vector combines the
interrupts in RFIF shown on page 156. Note
that these RF interrupts are rising- edge
triggered. Thus an interrupt is generated when
e.g. the SFD status flag goes from 0 to 1.
The RFIF interrupt flags are described in the
next section.
14.4.1 Interrupt registers
Two of the main interrupt control SFR registers
are used to enable the RF and RFERR
interrupts. These are the following:
• RFERR
• RF
: IEN0.RFERRIE
: IEN2.RFIE
Two main interrupt flag SFR registers hold the
RF and RFERR interrupt flags. These are the
following:
• RFERR
• RF
: TCON.RFERRIF
: S1CON.RFIF
Refer to section 11.5 on page 49 for details
about the interrupts.
The RF interrupt is the combined interrupt from
eight different sources in the radio. Two SFR
registers are used for setting the eight
individual RFIF radio interrupt flags and
interrupt enables. These are the RFIF and
RFIM registers.
CC2430 Data Sheet (rev. 2.1) SWRS036F
Page 155 of 211