[proposal] add rtl/test_setups

[stnolting]

This is a "spin-off" of #131

This PR is a proposal to add a rtl/test_setups folder, which provides two minimal test setup SoC configuration intended to be used as FPGA-, board- and toolchain-independent top entity for "first encounters". These setups are used in the updated User Guide (section "General Hardware Setup").

Both setups only provide an 8-bit wide GPIO.output port, clock, reset and UART RX & TX (only for the bootloader setup). Both setups also provide a minimal set of configuration generics: internal memory size configurations, clock speed.

• rtl/test_setups/neorv32_test_setup_approm.vhd uses internal IMEM as ROM, pre-initialized with software application
• rtl/test_setups/neorv32_test_setup_bootloader.vhd uses internal IMEM as RAM, software application upload vie UART + bootloader

The documentation (data sheet and user guide; READMEs) and the GHDL setup script have been modified accordingly.

[umarcor]

Athough not ready yet, I wonder how would the "load app from SPI flash" fit in these test_setups. Would that be included in the "direct" case, or would it be a third test setup?

Other than that, I like where this is heading!

[stnolting]

Athough not ready yet, I wonder how would the "load app from SPI flash" fit in these test_setups. Would that be included in the "direct" case, or would it be a third test setup?

I intentionally left this out. Booting from SPI flash seems like a "pro option". The idea of these (basic) test setups is to be as minimalist as possible to only show the basic configuration (and boot) setups.

Other than that, I like where this is heading!

🎉 😄 👍

[stnolting]

I think this can be merged, right? The changes shouldn't interfere with anything (I think).

[stnolting]

For the records:

• fixed typo in new test setups' VHDL file (entity & architecture names = file names)
• the Vivado and Quartus example setups now use the new rtl/test_setups/neorv32_test_setup_bootloader.vhd test setup template, which is pretty much identical to the old test setup from templates/
• removed the now-obsolete rtl/templates/processor/neorv32_ProcessorTop_Test.vhd