REGISTER SUMMARY
M68HC16 Z SERIES
D-28
USER’S MANUAL
D.4.4 ROM Bootstrap Words
Typically, CPU16 reset vectors reside in non-volatile memory and are fetched when
the CPU16 comes out of reset. These four words can be used as reset vectors with
the contents specified at mask time. The content of these words cannot be changed.
On generic (blank ROM) MC68HC16Z2 and MC68HC16Z3 devices, ROMBS[0:3] are
masked to $0000. When the ROM on the MC68HC16Z2 and MC68HC16Z3 is masked
with customer specific code, ROMBS[0:3] respond to system addresses $00000 to
$00006 during the reset vector fetch if BOOT = 0.
ROMBS0 — ROM Bootstrap Word 0
$YFF830
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NOT USED
ZK[3:0]
SK[3:0]
PK[3:0]
ROMBS1 — ROM Bootstrap Word 1
$YFF832
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PC[15:0]
ROMBS2 — ROM Bootstrap Word 2
$YFF834
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SP[15:0]
ROMBS3 — ROM Bootstrap Word 3
$YFF836
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IZ[15:0]
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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