[Oberon] Hardware versus software development.
joerg.straube at iaeth.ch
Fri Oct 31 16:31:12 CET 2014
I know. I had the following step-by-step approach in mind
1) - try to find another board, possibly with more memory for future use
- port the Verilog code to the new board.
- whole Oberon system stays untouched
2) introduce color
- SW decision (Oberon)
Assuming I have one bit per R-G-B: How do I represent the color in the
framebuffer? RGB in 3 separate planes or RGB as 3 consecutive bits.
- HW decision (Verlog)
There, I have to decide with RISC5 or with RISC6.
RISC5: I stay with 1 GB, I allocate more memory to video, and have less
for code, heap and stack.
RISC6: increase address bus by 1 and hence add another 1GB
From: skulski at pas.rochester.edu [mailto:skulski at pas.rochester.edu]
Sent: Freitag, 31. Oktober 2014 15:41
To: Joerg Straube
Cc: skulski at pas.rochester.edu; oberon at lists.inf.ethz.ch
Subject: Hardware versus software development.
> With RISC5 you dont touch the Oberon
> code anymore with new HW.
This is not true. The new Oberon System must be partitioned into its core
and the device drivers. The core (or kernel, if you wish) can stay intact.
But the device drivers must be adopted to the HW. The video is a good
example. In the published version it is a single bit plane. The RGB
signals are wired together. The video part is not really supporting color
because color is not present in the HW design. It is clearly not a nice
solution and the video HW needs to get modified. In fact, Nexys-4 provides
color out the box. So the Nexys version of The System needs to get
modified to use the provided video HW.
Are the driver modules part of The System? I would not argue this. The
point is that the drivers need be adjusted to the HW. In this sense one
has to touch the system. Being able to modify both the HW and the SW is
the whole point of this project in my opinion. A good introduction can be
found in the books by Pong P. Chu.
The really exciting prospect is that once you adopt the FPGA Oberon
System, you will soon be buying these books and you will very quickly
become a proficient FPGA developer, before you even notice it happenning.
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