RX610 Group
26. ROM (Flash Memory for Code Storage)
R01UH0032EJ0120 Rev.1.20
Page 856 of 1006
Feb 20, 2013
(1) Transferring Firmware to the FCU RAM
FCU commands can only be used if the FCU RAM holds the firmware for the FCU. The FCU RAM does not hold the
FCU firmware immediately after the chip has been booted up, so the firmware must be copied from the FCU firmware
area to the FCU RAM. Furthermore, when the FCUERR bit in FSTATR1 is set to 1, the FCU must be reset and the
firmware recopied because the firmware stored in the FCU RAM may have been corrupted.
Figure 26.12 shows the flow of the procedure for transferring firmware to the FCU RAM. Before writing data to the FCU
RAM, set FENTRYR to 0000h and stop the FCU. See section 12, DMA Controller (DMAC), for information on setting
up the DMAC to handle data transfer.
Other than 0000h
0000h
FENTRYR
check
Write C401h to
FCURAME
Copy to FCU RAM
Clear the FENTRY1 and
FENTRY0 bits
See section 26.6.4.1 (2), Switching to ROM Read Mode.
Enable access to the FCU RAM.
Copy the FCU firmware to the FCU RAM
Transfer source: FEFF E000h to FEFF FFFFh (FCU firmware area)
Transfer destination: 007F 8000h to 007F 9FFFh (FCU RAM area)
Start
End
Figure 26.12 Procedure for Firmware Transfer to FCU RAM
(2) Jumping to Locations in On-chip RAM
Since fetching instructions from the ROM is not possible while the ROM is being programmed or erased, code has to be
executed from an area other than the ROM. Copy the required program code to on-chip RAM and then make execution
jump to the address where the code starts in on-chip RAM.
(3) Transition to ROM P/E Mode
The FCU is placed in ROM P/E mode by the settings of the FENTRY1* or FENTRY0 bit in FENTRYR and of
FWEPROR. Details are given in section 26.6.4.1 (3)Switching to ROM P/E Normal Mode.
Note: * Cannot be used in a product whose ROM size is equal to or smaller than 1 Mbyte.