CC2430 Datasheet, PDF (191/234 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
reaches zero, program execution is halted
and the interrupt IRQ_CSP_STOP is
asserted. The CSPT register will not be
decremented if the CPU writes 0xFF to
this register.
Note: If the CSPT register compare
function is not used, this register must be
set to 0xFF before the program execution
is started.
14.34.3 Program Execution
After the instruction memory has been
filled, program execution is started by
writing the immediate command strobe
instruction ISSTART to the RFST register.
The program execution will continue until
either the instruction at last location has
been executed, the CSPT data register
contents is zero, a SSTOP instruction has
been executed, an immediate ISSTOP
instruction is written to RFST or until a
SKIP instruction returns a location beyond
the last location in the instruction memory.
Immediate Command Strobe instructions
may be written to RFST while a program is
being executed. In this case the
Immediate instruction will bypass the
instruction in the instruction memory,
which will be completed once the
Immediate instruction has been
completed.
During program execution, reading RFST
will return the current instruction being
executed. An exception to this is the
execution of immediate command strobes,
during which RFST will return C0h.
14.34.4 Interrupt Requests
The CSP has three interrupts flags which
can produce the RF interrupt vector.
These are the following:
• IRQ_CSP_STOP: asserted when
the processor has executed the
last instruction in memory and
when the processor stops due to a
SSTOP or ISSTOP instruction or
CSPT register equal zero.
• IRQ_CSP_WT: asserted when the
processor continues executing the
next instruction after a WAIT W or
WAITX instruction.
• IRQ_CSP_INT: asserted when the
processor executes an INT
instruction.
14.34.5 Random Number Instruction
There will be a delay in the update of the
random number used by the RANDXY
instruction. Therefore if an instruction,
RANDXY, that uses this value is issued
immediately after a previous RANDXY
instruction, the random value read may be
the same in both cases.
14.34.6 Running CSP Programs
The basic flow for loading and running a
program on the CSP is shown in Figure
56.
When program execution stops due to end
of program the current program remains in
program memory so that the same
program can be run again by starting
execution once again with the ISSTART
command. However, when program
execution is stopped by the SSTOP or
ISTOP instruction, the program memory
will be cleared.
.
CC2430 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A
Page 191 of 232