RX610 Group
26. ROM (Flash Memory for Code Storage)
R01UH0032EJ0120 Rev.1.20
Page 851 of 1006
Feb 20, 2013
26.6.4
FCU Command Usage
The set of FCU commands consists of commands for FCU mode transitions, actually programming or erasing the ROM,
error processing, and suspension and resumption. The following passages describe the various commands. For a
description of the modes and states where the respective commands are acceptable, see section 26.6.3, Connections
between FCU Modes and Commands.
26.6.4.1
Mode Transitions
This subsection covers the commands for mode transitions. For an illustration of the various transitions between modes,
see figure 26.5.
(1) Switching to ROM P/E Mode
A transition to ROM P/E mode is required before executing an FCU command for the ROM becomes possible.
Setting the FENTRY0 or FENTRY1* bit in FENTRYR to 1 causes a transition to ROM P/E mode for programming and
erasure of the corresponding address range.
Before actually proceeding to program or erase the ROM, enable programming and erasure by writing 01h as a byte to
FWEPROR (see section 26.2.15, Flash Write Erase Protection Register (FWEPROR)).
Write to FENTRYR
Set ROM P/E mode
When setting the FENTRY1 bit to 1: Write AA02h
When setting the FENTRY0 bit to 1: Write AA01h
End
Start
Write 01h to FWEPROR
Figure 26.6 Procedure for Transition to ROM P/E Mode
(2) Switching to ROM Read
Mode
High-speed reading of the ROM requires clearing of the FENTRY0 or FENTRY1* bit in FENTRYR, which places the
FCU in ROM read mode.
Writing of 02h to FWEPROR is also required to disable programming and erasure (see section 26.2.15, Flash Write
Erase Protection Register (FWEPROR).
Before switching the FCU from P/E mode to read mode, ensure that all processing of FCU commands has been
completed and that the FCU has not detected an error.
Note: * Cannot be used in a product whose ROM size is equal to or smaller than 1 Mbyte.
Summary of Contents for RX600 Series
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