We build a debugging solution for chosen development board DE0-Nano and for it especially developed extension board. Our solution enables us to debug software written for hardware processor in an FPGA device. We extended template system used for tutorials in the Laboratory for integrated circuits design (LNIV). The system includes 12 bit educational processor, which lacks a debugging unit. The debugging unit is described in VHDL language. Software that we used are Intel Quartus, ModelSim and PuTTY.
Function of debugging unit is control over processor operation capabilities and getting information of its state. We are using open source serial interface to connect it with a computer. We had to connect the interface with a bus of extension board and test it while all other periphery are using this bus as well. Next step was to interpret the data that we received through serial interface. For that reason we had to upgrade microprocessor unit. With set of commands that we chose we also determined what functions we would implement into our system. In the process we chose to use sign “r” to reset processor, to stop it with a sign ”s”, to enable it with “e” and to make it work in a step-by-step with “k”. We implemented as well commands to extract some data of processor state. To get a value of accumulator we send a sign “a” an for the program counter (PC) we chose “p”.
Final product of work presents a solution that covers all the goals set at the beginning.
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