N-Wire Enabling Methods; Starting Normal Operation After Reset And Respoc; Starting Debugger After Reset And Respoc - NEC V850ES/F 3-L Series User Manual

Chapter 23

23.3 N-Wire Enabling Methods

Table 23-2

23.3.1 Starting normal operation after RESET and RESPOC

Power
on
RESPOC
RESET
OCDM0
DRST
Figure 23-1

23.3.2 Starting debugger after RESET and RESPOC

Note
728
The current operation mode of the microcontroller is determined by
OCDM.OCDM0 and DRST:
Normal operation and debug mode control
DRST
0
1
For "normal operation" it has to be assured that the pins P05, P52...P55 are
available as port pins after either reset event. Therefore the software has to
perform OCDM.OCDM0 = 0 to make the pins available as port pins after
RESET.
Note that after any external reset via the RESET pin OCDM.OCDM0 is set to
"1" and the pins P05, P52...P55 are not available as application function pins
until the software sets OCDM.OCDM0 = 0.
"0"
reset normal operation
Start without N-Wire activation
The software has to set OCDM.OCDM0 = 1 for enabling the N-Wire interface
also upon a RESPOC event. Afterwards the debugger may start to establish
communication with the controller by setting the DRST pin to high level and to
take control over the CPU.
On start of the debugger the entire controller is reset, i.e. all registers are set to
their default states and the CPU's program counter is set to the reset vector
0000 0000 .
H
After RESPOC the controller is operating without debugger control. Thus all
CPU instructions until the software performs OCDM.OCDM0 = 1 can not be
debugged. To restart the user's program from beginning under the debugger's
control apply an external RESET after the debugger has started, as shown in
User's Manual U18743EE1V2UM00
OCDM.OCDM0
X
0
1
application software
sets OCDM.OCDM0PC = 0
"1"
reset normal operation
On-Chip Debug Unit
Mode
normal operation
on-chip debug