D12320VF25V Datasheet, PDF (761/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 17 ROM
When less than 128-byte programming is performed, data must total 128 bytes by adding the
invalid data. If the invalid data to be added is H'FF, the program processing period can be shorted.
[1] Select the on-chip program to be downloaded and the download destination.
When the PPVS bit of FPCS is set to 1, the programming program is selected.
Several programming/erasing programs cannot be selected at one time. If several programs are
set, download is not performed and a download error is returned to the source select error
detect (SS) bit in the DPFR parameter.
Specify the start address of the download destination by FTDAR.
[2] Program H'A5 in FKEY
If H'A5 is not written to FKEY for protection, 1 cannot be written to the SCO bit for download
request.
[3] 1 is written to the SCO bit of FCCS and then download is executed.
To write 1 to the SCO bit, the following conditions must be satisfied.
• RAM emulation mode is canceled.
• H'A5 is written to FKEY.
• The SCO bit writing is executed in the on-chip RAM.
When the SCO bit is set to 1, download is started automatically. When the SCO bit is returned
to the user procedure program, the SCO is cleared to 0. Therefore, the SCO bit cannot be
confirmed to be 1 in the user procedure program.
The download result can be confirmed only by the return value of the DPFR parameter. Before
the SCO bit is set to 1, incorrect judgement must be prevented by setting the DPFR parameter,
that is one byte of the start address of the on-chip RAM area specified by FTDAR, to a value
other than the return value (H'FF).
When download is executed, particular interrupt processing, which is accompanied by the bank
switch as described below, is performed as an internal microcomputer processing. Four NOP
instructions are executed immediately after the instructions that set the SCO bit to 1.
(a) The user-MAT space is switched to the on-chip program storage area.
(b) After the selection condition of the download program and the address set in FTDAR are
checked, the transfer processing is executed starting from the on-chip RAM address specified
by FTDAR.
(c) The SCO bits in FPCS, FECS, and FCCS are cleared to 0.
(d) The return value is set to the DPFR parameter.
(e) After the on-chip program storage area is returned to the user-MAT space, the user procedure
program is returned.
• In the download processing, the values are stored in the general registers other than ER0 and
ER1of the CPU.
Rev.7.00 Feb. 14, 2007 page 727 of 1108
REJ09B0089-0700