PEB 20560
Functional Block Description
Semiconductor Group
2-115
2003-08
2.9
On-chip Emulation (OCEM)
The On-chip Emulation (Debugger) allows “bugs” in the application software to be found
and corrected early in design cycle. It is implemented partly in hardware and partly in
software. It interprets functions such as Go, Abort, Stop, Data Read/Write and also
performes instruction and data breakpoints, program flow trace buffering and breakpoint
on event at operation cycle speed without additional off-chip hardware. Different
breakpoints can be set on:
Program Address
Data Address
Data Value
Single Step
Interrupt
Once a condition is met the On-Chip Emulation activates the TRAP mechanism causing
the kernel to suspend any action and jump into the service routine. An additional external
signal (STOP pin) is provided to stop in parallel any connected processing element.
Program flow tracing includes dynamic recording of program addresses. Those
addresses provide a full program flow graph of instruction being executed.
2.10
The
μ
P and the DSP communicate via a bidirectional mailbox according to a user
definable protocol. This mailbox includes two separate parts:
μ
P mailbox - enables transfer from the
μ
P to the OAK.
OAK mailbox - enable transfer from the OAK to the
μ
P.
Both parts includes a command register, 6
×
16 bits registers and a busy bit. The
commands syntax will be defined by the user. An example for some commands can be
found in the boot sequence definition within the DCU description.
Mailbox
2.10.1
The
μ
P mailbox includes six general purpose sixteen bit registers (MDTx), an 8-bit
command register (MCMD) and one 8-bit busy register (MBUSY). The registers MDTx
and MCMD can be written by the
μ
P and read by the OAK. MBUSY can be read by
μ
P.
A write of the
μ
P to the
μ
P mailbox command register generates an interrupt to the OAK
(INT2). Therefore, when the user wants to transfer more data the command register
must be written last.
A busy bit which can be read by the
μ
P (MBUSY) is set automatically after a write to the
μ
P command register and reset by a direct OAK write operation to it.
Users can define own opcodes (up to 256 opcodes) for the transfer direction from the
μ
P
to the OAK.
μ
P Mailbox