MC912DG128A Motorola, MC912DG128A Datasheet - Page 121

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

ITST2 — Interrupt Test Register 2
ITST3 — Interrupt Test Register 3
ITST0 — Interrupt Test Register 0
ITST1 — Interrupt Test Register 1
Resets
Power-On Reset
7-reset
MOTOROLA
RESET:
RESET:
RESET:
RESET:
ITC6
Bit 7
ITB6
ITE6
ITD6
Bit 7
Bit 7
Bit 7
0
0
0
0
ITC8
ITB8
ITE8
ITD8
6
0
6
0
6
0
6
0
These registers can only be read in special modes (read in normal mode
will return $00). Reading these registers at the same time as the interrupt
is changing will cause an indeterminate value to be read. These
registers can only be written in special mode.
There are four possible sources of reset. Power-on reset (POR), and
external reset on the RESET pin share the normal reset vector. The
computer operating properly (COP) reset and the clock monitor reset
each has a vector. Entry into reset is asynchronous and does not require
a clock but the MCU cannot sequence out of reset without a system
clock.
A positive transition on V
voltage level detector, or other external reset circuits, are the usual
source of reset in a system. The POR circuit only initializes internal
ITCA
ITDA
ITBA
ITEA
5
0
5
0
5
0
5
0
Resets and Interrupts
ITDC
ITCC
ITEC
ITBC
4
0
4
0
4
0
4
0
DD
ITDE
ITCE
ITEE
ITBE
causes a power-on reset (POR). An external
3
0
3
0
3
0
3
0
ITE0
ITF0
ITD0
ITC0
2
0
2
0
2
0
2
0
ITE2
ITF2
ITD2
ITC2
MC68HC912DT128A Rev 2.0
1
0
1
0
1
0
1
0
Resets and Interrupts
ITE4
Bit 0
ITF4
Bit 0
ITC4
ITD4
Bit 0
Bit 0
0
0
0
0
$001A
$001B
Resets
$0018
$0019
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