E1/E20/E2/E2 Lite Additional Document
R20UT1994EJ0900 Rev.9.00
Page 41 of 58
Jan.20.22
*1
The reset vector area is used by the program for the E1/E20/E2/E2 Lite when performing debugging
with the E1/E20/E2/E2 Lite. If the contents of the reset vector area are changed, control by the
E1/E20/E2/E2 Lite is no longer possible.
3.3.1
Securing an Area for the Debugging Monitor Program
You may need to secure the area to which the debugging monitor program is to be allocated. The monitor
program initializes the debugger communications interface and handles processing to make the CPU run or
break execution.
The user program or data must not be placed within 23 bytes of the on-chip debugging option byte, and
leave an area of at least 768 bytes*
1
before the address where the internal ROM area ends.
In addition, the reset vector must be changed if it points to an address to which the monitor program is
allocated.
[Securing the area]
Specifically securing the area for the monitor program is not necessarily required if the user program does
not use the area.
However, to avoid problems that may occur while the debugger is starting up, we recommend securing this
area in advance by using a build tool or some other means.
Notes:
1
The required area differs according to the state of usage of the pseudo-RRM/pseudo-DMM
function, the start/stop function (only supported by the E2/E2 Lite), and the monitoring point of
the extended function of the E2 (only supported by the E2).
Example (device with 256 Kbytes of on-chip ROM)
Pseudo-RRM/pseudo-DMM function, start/stop function, and monitoring point are not in use:
Monitor program is located at addresses 0x3FF00 to 0x3FFFF (256 bytes).
Pseudo-RRM/pseudo-DMM function, start/stop function, or monitoring point is in use:
Monitor program is located at addresses 0x3FE00 to 0x3FFFF (512 bytes).
Pseudo-RRM/pseudo-DMM function and start/stop function are in use*2:
Monitor program is located at addresses 0x3FD00 to 0x3FFFF (768 bytes).
2
A monitoring point cannot be used with the pseudo-RRM/pseudo-DMM function or the
start/stop function.
