Renesas M16C/60 Series, Руководство пользователя

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R01UH0136EJ0210 Rev.2.10 Page 138 of 800
Jul 31, 2012
M16C/64A Group 11. Bus
11. Bus
11.1 Introduction
Two types of buses are available:
•
Internal bus in the MCU
•
External bus which is used to access to external devices in memory expansion mode or
microprocessor mode
11.2 Registers
Table 11.2 lists bus related registers. Refer to 10. “Processor Mode” for registers PM0 and PM1. Refer to
30. “Flash Memory” for the FMR1 register.
Table 11.1 Bus Specifications
Item Specification
Internal bus
•
Used in all processor modes
•
Separate bus
•
16-bit data bus width
•
0 or 1 software waits can be inserted
External bus
•
Used in memory expansion mode or microprocessor mode
•
Separate bus or multiplexed bus selectable
•
Data bus width selectable (8 or 16 bits)
•
Number of address buses selectable (12, 16, or 20 buses)
•
4 chip select outputs
CS0
to
CS3
•
Combinations of read and write signals selectable (
RD
,
BHE
,
WR
or
RD
,
WRL
,
WRH
)
•
RDY
available
•
0 to 3 software waits can be inserted
•
Memory area expansion function (up to 4 MB) (refer to 12. “Memory Space Expansion
Function”)
•
3 V or 5 V interface
Table 11.2 Registers
Address Register Symbol Reset Value
0004h Processor Mode Register 0 PM0
0000 0000b
(CNVSS pin is low)
0000 0011b
(CNVSS pin is high)
0005h Processor Mode Register 1 PM1 0000 1000b
0008h Chip Select Control Register CSR 01h
001Bh Chip Select Expansion Control Register CSE 00h
0221h Flash Memory Control Register 1 FMR1 00X0 XX0Xb