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Bus Controller (BC)
8-28
8.8 Operation Clocks
MCLK, IOCLK, and SYSCLK are used as BC operation clocks. Table 8-8-1 shows the ratio of each clock versus
the oscillation input clock (OSCI).
Table 8-8-1 Frequency Ratios of BC Operation Clocks
Oscillation mode Clock control register setting SYSCLK MCLK IOCLK
CKSEL PLL mutiplier mutiplier mutiplier
MCK[1:0] = 10 4 1
H Using MCK[1:0] = 01 1 2 1/2
MCK[1:0] = 00 1 1/4
L Not using Not using 1/2 1/2 1/8
For details, refer to Chapter 6, “Clock Generator.”
8.9 Mode Settings
The values of external input pins MMOD1 to 0 and EXMOD1 to 0 set the external memory mode, block 0 bus
width, and separate/common mode for the address pins and data pins. The various mode settings that can be made
through the external pins are shown in Table 8-9-1.
Table 8-9-1 Mode Settings by the BC External Pins
Selection Setting
Mode name Address/data
Block 0 bus width*
MMOD1 MMOD0 EXMOD1 EXMOD0
Separate
8 bits L H L L
Memory extension mode
16 bits L H L H
Common
8 bits L H H L
16 bits L H H H
Separate
8 bits H L L L
Processor mode
16 bits H L L H
Common
8 bits H L H L
16 bits H L H H
* Set the bus widths for blocks 1 to 3 through their respective memory control registers.