MC9S12T64 Datasheet, PDF (115/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Operating Modes
Operating Modes
If MODA=1, then MODC, MODB, MODA are write never.
If MODC=MODA=0, then MODC, MODB, MODA are write anytime
except that you cannot change to or from peripheral mode.
If MODC=1, MODB=0 and MODA=0, then MODC is write never,
MODB, MODA are write once, except that you cannot change to
peripheral, special test, special single chip, or emulation modes.
Table 21 MODC, MODB, MODA Write Capability⁽¹⁾
MODC MODB MODA
Mode
MODx Write Capability
0
0
0 Special Single Chip
MODC, B, A write anytime but not to 110⁽²⁾
0
0
1 Emulation Exp Narrow
no write
0
1
0 Special Test
MODC, B, A write anytime but not to 110⁽²⁾
0
1
1 Emulation Exp Wide
no write
1
0
0 Normal Single Chip
MODC write never, MODB, A write once but
not to 110
1
0
1 _{Normal Expanded Narrow} ⁽³⁾
no write
1
1
0 Special Peripheral
no write
1
1
1 _{Normal Expanded Wide} ⁽³⁾
no write
1. No writes to the MOD bits are allowed while operating in a SECURED mode.
2. If you are in a special single chip or special test mode and you write to this register, changing to normal single chip
mode, then one allowed write to this register remains even if you write to a special mode. If you write to normal
expanded or emulation mode, then no writes remain.
3. The external bus can not be used for memory expansion purpose with external memory devices, since this MCU
does not have the PIX[5:0]/XADDR[19:14] pins to indicate page number.
IVIS — Internal Visibility (for both read and write accesses)
This bit determines whether internal accesses generate a bus cycle
that is visible on the external bus. Refer to the page 110 about Internal
Visibility.
Normal: write once
Emulation: write never
Special: write anytime
MOTOROLA
Operating Modes
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MC9S12T64Revision 1.1.1
115