This design is currently a work in progress. The goal is to place a ZipCPU onto a $30 Max1000 FPGA, as sold by Arrow and Trenz Electronics.
If all goes well, this will include access to ...
The on-board SDRAM. This includes not only the Verilog code to access this SDRAM, but also a simulation component for the SDRAM, as well as an AutoFPGA script to add (or remove) the SDRAM from this build.
This capability now works.
A dual-I/O flash, running in both XIP (Execute in Place) mode as well as a debug-bus configuration override. As with the SDRAM, this will include not only the Verilog code, but also a simulation component and an AutoFPGA script to add (or remove) the flash from this build.
The flash controller now works as well.
The on-board MEMS motion sensor.
This last piece remains a work in progress.
The design now builds and runs, both in simulation and on hardware, using the flash controller.
The SDRAM controller now passes a memory test, and should be ready to use.
The I/O drivers are currently Intel generated IP. These still need to be replaced by references to the actual underlying drivers. However, if you create the I/O drivers yourself, then you can run the design as is.
First, install Quartus, Verilator, and the ZipCPU toolchain.
To run from simulation, build the design (make) and then cd into the sim/verilated. Type "main_tb" to start the simulator. "main_tb -d" will start creating a VCD file at the same time. "main ../../sw/board/cputest" will load the CPU test into the ZipCPU. While running the simulation, you can telnet into "localhost 6956" to interact with the serial port of the design. You can also use the wbregs program to read and set various addresses peripheral and otehrwise within the design.
For example, "wbregs stopwatch 1" will start the stopwatch capability. "wbregs timer 0x130" will start a timer counting down from one minute and thirty seconds. "wbregs clock 0x210837" will set the RTC clock time to 9:08:37 PM.
To run the design on the device itself, build the design and then load it into the device (see the vendor's instructions) and then run "netuart" from the sw/host directory. You may need to give it the name of your serial port, as in "netuart /dev/ttyUSB0". (Both the simulator and netuart use the same network port, so you'll only be able to run one of these at a time.) You should then be able to use the wbregs program to interact with the various registers within the design. To load the cputest, run "zipload -r ../board/cputest" from the sw/host directory. You should then see a series of tests results posted on the serial port.
To reconfigure the design, such as to add or remove device or to adjust the amount of block RAM, you'll need to adjust the files in the auto-data directory and re-run AutoFPGA.