Chapter 16 Debug Module (DBGV1)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor
491
16.3.2.9
Debug Comparator A Extended Register (DBGCAX)
76543210
R
PAGSEL
EXTCMP
W
Reset
0
00000
Figure 16-15. Debug Comparator A Extended Register (DBGCAX)
Table 16-19. DBGCAX Field Descriptions
Field
Description
7:6
PAGSEL
Page Selector Field — If DBGEN is set in DBGC1, then PAGSEL selects the type of paging as shown in
DPAGE and EPAGE are not yet implemented so the value in bit 7 will be ignored (i.e., PAGSEL values of 10 and
11 will be interpreted as values of 00 and 01, respectively).
In BKP mode, PAGSEL has no meaning and EXTCMP[5:0] are compared to address bits [19:14] if the address
is in the FLASH/ROM memory space.
5:0
EXTCMP
Comparator A Extended Compare Bits — The EXTCMP bits are used as comparison address bits as shown
in
Table 16-20 along with the appropriate PPAGE, DPAGE, or EPAGE signal from the core.
Table 16-20. Comparator A or B Compares
Mode
EXTCMP Compare
High-Byte Compare
BKP1
Not FLASH/ROM access
No compare
DBGCxH[7:0] = AB[15:8]
FLASH/ROM access
EXTCMP[5:0] = XAB[19:14]
DBGCxH[5:0] = AB[13:8]
DBG2
2 See Figure 16-10 (note that while this gure provides extended comparisons for comparator C, the gure also pertains to comparators A and B in DBG mode only).
PAGSEL = 00
No compare
DBGCxH[7:0] = AB[15:8]
PAGSEL = 01
EXTCMP[5:0] = XAB[21:16]
DBGCxH[7:0] = XAB[15:14], AB[13:8]
PAGSEL
EXTCMP
DBGCXX
0
54321
BIT 0
SEE NOTE 1
PORTK/XAB
XAB21
XAB20
XAB19
XAB18
XAB17
XAB16
XAB15
XAB14
PPAGE
PIX7
PIX6
PIX5
PIX4
PIX3
PIX2
PIX1
PIX0
SEE NOTE 2
NOTES:
1. In BKP mode, PAGSEL has no functionality. Therefore, set PAGSEL to 00 (reset state).
2. Current HCS12 implementations are limited to six PPAGE bits, PIX[5:0].
Figure 16-16. Comparators A and B Extended Comparison in BKP Mode
BKP
MODE
