M16C6N4 Datasheet, PDF (52/406 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

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M16C/6N Group (M16C/6N4)
6. Processor Mode
6. Processor Mode
6.1 Types of Processor Mode
Three processor modes are available to choose from: single-chip mode, memory expansion mode, and
microprocessor mode. Table 6.1 shows the features of these processor modes.
Table 6.1 Features of Processor Modes
Processor Mode
Access Space
Single-chip Mode
SFR, internal RAM, internal ROM
Memory Expansion Mode
Microprocessor Mode
NOTE:
1. Refer to 7. Bus.
SFR, internal RAM, internal ROM,
external area ⁽¹⁾
SFR, internal RAM, external area ⁽¹⁾
Pins Which are Assigned I/O Ports
All pins are I/O ports or
peripheral function I/O pins
Some pins serve as bus control pins ⁽¹⁾
Some pins serve as bus control pins ⁽¹⁾
6.2 Setting Processor Modes
Processor mode is set by using the CNVSS pin and the PM01 to PM00 bits in the PM0 register.
Table 6.2 shows the processor mode after hardware reset. Table 6.3 shows the PM01 to PM00 bits set
values and processor modes.
Table 6.2 Processor Mode After Hardware Reset
CNVSS Pin Input Level
Processor Mode
VSS
Single-chip mode
VCC ^{(1) (2)}
Microprocessor mode
NOTES:
1. If the microcomputer is reset in hardware by applying VCC to the CNVSS pin, the internal ROM
cannot be accessed regardless of PM01 to PM00 bits.
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2. The multiplexed bus cannot be assigned to the entire CS space.
Table 6.3 PM01 to PM00 Bits Set Values and Processor Modes
PM01 to PM 00 Bits
Processor Mode
00b
Single-chip mode
01b
Memory expansion mode
10b
Do not set a value
11b
Microprocessor mode
Rewriting the PM01 to PM00 bits places the microcomputer in the corresponding processor mode regardless of
whether the input level on the CNVSS pin is “H” or “L”. Note, however, that the PM01 to PM00 bits cannot
be rewritten to “01b” (memory expansion mode) or “11b” (microprocessor mode) at the same time the
PM07 to PM02 bits are rewritten. Note also that these bits cannot be rewritten to enter microprocessor
mode in the internal ROM, nor can they be rewritten to exit microprocessor mode in areas overlapping the
internal ROM.
If the microcomputer is reset in hardware by applying VCC to the CNVSS pin (hardware reset), the internal
ROM cannot be accessed regardless of PM01 to PM00 bits.
Figures 6.1 and 6.2 show the processor mode related registers. Figure 6.3 shows the memory map in
_____
single-chip mode. Figures 6.4 to 6.7 show the memory map and CS area in memory expansion mode and
microprocessor mode.
Rev.2.30 Oct 24, 2005 page 34 of 376
REJ09B0009-0230