Freescale Semiconductor StarCore SC140 - Manual (Page 166)

4-56 SC140 DSP Core Reference Manual
Event Detection Unit (EDU) Channels and Registers
In order to detect a watchpoint on a PC range, one EDCA is enough. In order to detect a watchpoint on a
data address range, two EDCAs are required. When configuring two EDCAs to detect a watchpoint to an
address range, one EDCA should be configured to detect the range on bus A, and the other EDCA to detect
CBCS
Bits 7–6 Comparator B Condition Selection —
Used to select one of these four results
from comparator B:
• Equal to
• Not equal to
• Greater than
• Less than
00 = Equal to EDCA_REFB
01 = Not equal to EDCA_REFB
10 = Greater than EDCA_REFB
11 = Less than EDCA_REFB
CACS
Bits 5–4 Comparator A Condition Selection —
Used to select one of these four results
from comparator A:
• Equal to
• Not equal to
• Greater than
• Less than
00 = Equal to EDCA_REFA
01 = Not equal to EDCA_REFA
10 = Greater than EDCA_REFA
11 = Less than EDCA_REFA
ATS
Bits 3–2 Access Type Selection — These bits
are used to select the type of memory
access that should be detected by the
event detection channel. The possible
memory access types are:
• Read access
• Write access
• Read or write access
00 = Read access
01 = Write access
10 = Read or write access
11 = Reserved
BS
Bits 1–0 Bus Selection — Used to select which
address bus or buses should be
sampled for comparison by comparator
A and/or by comparator B. The possible
buses that can be chosen by these bits
are PC, XABA, and XABB.
If XABA and/or XABB are the selected
buses, bus XABA is compared to the
EDCA_REFA register while XABB is
compared to the EDCA_REFB register.
If CS bits are set to 11, then setting BS
bits to 10 enables the user to set a
watchpoint on an address when it is not
known whether the address to be used
for accessing memory is on XABA or
XABB. In this case, the user must set
both reference value registers with the
address to be detected.
If the BS bits are set to 10, then the CS
bits must be set to either 10 or 11.
00 = XABA
01 = XABB
10 = XABA and XABB
11 = PC
Table 4-19. EDCA_CTRL Description (Continued)
Name Description Settings