USBB17RX78K4-XXX NEC Electronics, USBB17RX78K4-XXX Datasheet - Page 84

• Manufacturer Part Number: USBB17RX78K4-XXX
• Description: 78K/4 series realtime OS
• Manufacturer: NEC Electronics

When creating a cyclic handler, be careful about the following points.
(1) The cyclic handler can be mapped in the 1MB memory space. (Large model only)
(2) The cyclic handler is invoked with the “br rg” command from the timer dispatch routine. For this reason, it is
(3) After ending the cyclic handler processing, be sure to return to the timer dispatch routine “?tm_ret”. Please
(4) When switching to another register bank in the cyclic handler, return to the original register bank first before
(5) In the timer dispatch routine, the “rg7, rg6, rg5, rp1, and rp0” registers are stored on the stack when
handled in the same manner as an interrupt handler; therefore, the system calls that can be issued are only
the “i
from a cyclic handler.
code the cyclic handler processing as follows:
returning to the timer dispatch routine.
interrupted. Therefore, when using the “rg4, rp3, and rp2” registers in the cyclic handler, please restore the
value to the original one when returning to the timer dispatch routine.
´´´
_
´´´
[Cyclic handler address]:
” system calls. However, the “i
APPENDIX 4
public
extern
[Cyclic handler processing]
br
cyc_ptr:
public
extrn
push
sel
push
pop
pop
br
[cyclic handler address]
?tm_ret
!?tm_ret
EXAMPLE OF CYCLIC HANDLER CODING
c y c l i c h a n d l e r p r o c e s s i n g
cyc_ptr
psw
rb6
rp2
rp2
psw
!?tm_ret
?tm_ret
´´´
_
´´´
” system calls targeting cyclic handlers cannot be issued
¬
¬
¬
¬
¬
(4)
(5)
(5)
(4)
(3)
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