Operating Modes
Internal Resource Mapping
68HC(9)12DG128 Rev 1.0
MOTOROLA
Operating Modes
71
13-modes
Test mode
Program space
expansion
In special mode and for test purposes only, the 128K bytes of Flash
EEPROM (68HC912DG128) or ROM (68HC12DG128) can be
accessed through a test program space window of 32K bytes. This
window replaces the user’s program space window to be able to access
an entire array. In special mode and with ROMTST bit set in MISC
register, a program space is located from $8000 to $FFFF. Only two
page indices are used to point to one of the four 32K byte arrays. They
can be viewed as expanded addresses X16 and X15.
Page Index
register
descriptions
Read and write anytime
Writing to the port does not change the pin states when it is configured
for page index emulation output.
This port is associated with the page index emulation pins. When the
port is not enabled to emulate page index, the port pins are used as
general-purpose I/O. Port K bit 3 is always a general purpose I/O pin.
This register is not in the memory map in peripheral or expanded modes
when the EMK control bit in MODE register is set.
Table 15 Test mode program space Page Index
Page Index 2
(PPAGE bit 2)
0
0
1
1
Page Index 1
(PPAGE bit 1)
0
1
0
1
Page Index 0
(PPAGE bit 0)
X
X
X
X
Flash register space
Page
32K byte array Page 0
32K byte array Page 1
32K byte array Page 2
32K byte array Page 3
Flash array
68HC912DG128
00FEE32K
01FEE32K
10FEE32K
11FEE32K
ROM array
68HC12DG128
00ROM32K
01ROM32K
10ROM32K
11ROM32K
PORTK
— Port K Data Register
$00FC
Bit 7
6
5
4
3
2
1
Bit 0
PORT
PK7
0
0
0
PK3
PK2
PK1
PK0
Emulation
ECS
0
0
0
-
PIX2
PIX1
PIX0
RESET:
-
0
0
0
-
-
-
-