Z16F2800100ZCOG Zilog, Z16F2800100ZCOG Datasheet - Page 324

• Manufacturer Part Number: Z16F2800100ZCOG
• Description: DEV KIT FOR Z16F ZNEO
• Manufacturer: Zilog
• Series: ZNEO™r
• Type: MCUr

Specifications of Z16F2800100ZCOG

• Contents: Evaluation Board, Software and Documentation
• For Use With/related Products: Z16F Series
• For Use With: 269-4661 - KIT ACC ETHERNET SMART CABLE
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 269-4537

PS022008-0810
Reading Memory CRC
Breakpoints
Instruction Trace
Data read from or written to the OCD occurs one byte at a time. Therefore, memory read
and write operations occur one byte at a time. Operations that occur on multi-byte words
does not occur concurrently.
Since the ZNEO device has such a large memory space and the debug interface is serial,
reading massive amounts of data during debugging is time consuming. The OCD hard-
ware has the capability of calculating a cyclic redundancy check (CRC) on memory to
allow memory caching mechanisms to be used by the host debugging software. This CRC
verifies that the contents of a memory cache has not changed.
When the read CRC command is issued, the OCD hardware steals the CPU bus during the
entire read operation. The length of time it takes to generate the CRC is equal to the
amount of time it takes to read the memory used in the CRC calculation.
The OCD hardware also has the capability of returning separate CRCs for each 4K block
of memory. This is used by software to determine the portions of memory, which have
been modified when the cache for a large block of memory is invalidated.
Software Breakpoints
Breakpoints are generated when the CPU executes the
enabled. If breakpoints are not enabled, the
exception vector and set the illegal instruction status bit.
If a Breakpoint is generated, the OCD is configured to automatically enter Debug Halt
mode or to just loop on the instruction. If the OCD is configured to loop on the instruction,
the CPU is still able to service DMA and interrupt requests in the background. Software
polls the
Breakpoint.
Hardware Breakpoint
There are four hardware breakpoints on the ZNEO Device. When enabled, a breakpoint is
generated when the program counter matches the value in the breakpoint register, or when
a memory access occurs at the address in the breakpoint register. A data watchpoint
watches a range of addresses by selecting how many lower address bits are ignored.
Trace Overview
The ZNEO has the ability to trace the instruction flow. If enabled, it uses existing Memory
to store the Program Counter data each time a change in execution flow occurs. This
requires you to allocate memory space to hold the trace information.
DBGBRK
bit of the DBGCTL register to determine if the OCD has reached a
P R E L I M I N A R Y
BRK
instruction will vector to the system
BRK
instruction and breakpoints are
Product Specification
ZNEO
On-Chip Debugger
Z16F Series
308