RX610 Group
3. Operating Modes
R01UH0032EJ0120 Rev.1.20
Page 94 of 1006
Feb 20, 2013
3.3
Details of Operating Modes
3.3.1
Single-Chip Mode
In this mode, the on-chip ROM is enabled or disabled, the external bus is disabled (EXBE bit = 0 in SYSCR0), and all
I/O ports can be used as input/output ports.
The on-chip ROM is enabled when this LSI is started. While the on-chip ROM is enabled (ROME bit = 1 in SYSCR0), it
can be disabled by clearing the ROME bit to 0. While the on-chip ROM is disabled (ROME bit = 0), it cannot be enabled
by setting the ROME bit to 1.
Setting the EXBE bit in SYSCR0 to 1 causes a transition to on-chip ROM enabled extended mode or on-chip ROM
disabled extended mode where the external bus is available.
3.3.2
On-Chip ROM Enabled Extended Mode
In this mode, the on-chip ROM is enabled (ROME bit = 1 in SYSCR0) and the external bus is available as external
extended mode (EXBE bit = 1 in SYSCR0). This mode allows some I/O ports to be used as data bus input/output,
address bus output, or bus control signal input/output. For details, see section 14, I/O Ports.
The external bus width can be changed by the setting of external bus width selection (BSIZE[1:0] bits in CSiCNT (i = 0
to 7)). For details, see section 11, Buses.
Writing 0 to the EXBE bit causes a transition to single-chip mode (on-chip ROM enabled).
Writing 0 to the ROME bit causes a transition to on-chip ROM disabled extended mode.
3.3.3
On-Chip ROM Disabled Extended Mode
In this mode, the on-chip ROM is disabled (ROME bit = 0 in SYSCR0) and the external bus is available as external
extended mode (EXBE bit = 1 in SYSCR0). This mode allows some I/O ports to be used as data bus input/output,
address bus output, or bus control signal input/output. For details, see section 14, I/O Ports.
The external bus width can be changed by the setting of external bus width selection (BSIZE[1:0] bits in CSiCNT (i = 0
to 7)). For details, see section 11, Buses.
In this mode, the on-chip ROM cannot be enabled by setting the ROME bit to 1.
Writing 0 to the EXBE bit causes a transition to single-chip mode (on-chip ROM disabled).
3.3.4
Boot Mode
Boot mode is provided for the flash memory. This mode functions in the same manner as single-chip mode except for
data write/erase to the flash memory. For details, see section 26, ROM (Flash Memory for Code Storage), and section 27,
Data Flash (Flash Memory for Data Storage).
3.3.5
User Boot Mode
User boot mode is provided for the flash memory. This mode functions in the same manner as single-chip mode except
for data write/erase to the flash memory. For details, see section 26, ROM (Flash Memory for Code Storage), and section
27, Data Flash (Flash Memory for Data Storage).