MPLAB ICE 4 can communicate with Flash silicon via the ICSP and other target interfaces. It uses the debug executive located in dedicated memory. For legacy 8-bit PIC devices, the debug executive resides in Program memory.
The debug executive doesn't run while in Run mode, so there is no throughput reduction when running your code, i.e., the debugger doesn’t ‘steal’ any cycles from the target device.
MPLAB ICE 4 communicates using the debug executive located in a dedicated area of memory. The debug executive is streamlined for more efficient communication. The debugger contains an FPGA, large SRAM Buffers (1Mx8), and a High-Speed USB interface. Program memory image is downloaded and is contained in the SRAM to allow faster programming. The FPGA in the debugger serves as an accelerator for interfacing with the device in-circuit debugger modules.
Traditional debuggers use a special debugger chip (-ME) for monitoring. There is no -ME with theMPLAB ICE 4, so there are no buses to monitor externally. With the MPLAB ICE 4, rather than using external breakpoints, the built-in breakpoint circuitry of the debug engine is used – the buses and breakpoint logic are monitored inside the part.
Yes. You can break based on a value in a data memory location. You can also do sequenced breakpoints, where several events have to occur before it breaks. However, you can only do two sequences. You can also do the AND condition and do PASS counts.
The standard ICSP-RJ11 cable maximum clock frequency is approximately 15 MHz. Device interrogation during debugging occurs at frequencies below this rate regardless of the CPU clock rate. However, some advanced functions are synchronous to the CPU bus cycle (like instrumented trace and data capture). During data capture and when the CPU runs at its highest speed (40 MIPS for example), the actual clock rate through the cable would exceed 15 MHz. In these instances, trace and data capture cannot run reliably and the ICSP-RJ11 cable cannot be used.
There is no cycle stealing with the MPLAB ICE 4. The output of data is performed by the state machine in the silicon.
The MPLAB ICE 4 is capable of debugging at any device speed as specified in the device’s data sheet.