Commit Graph

18 Commits

Author SHA1 Message Date
8de9e10f39 avoid bouncing when starting/resetting 2021-08-11 22:26:35 +02:00
8fde6f1e74 some comments and minor fixes 2021-08-11 21:23:00 +02:00
02a19ef783 fixed horizontal offset error
Basically, the LPM instruction (3 cycles) does not always take 3 cycles,
(I think because of the timing needed to read the Flash memory),
and this disrupts the timing of the signal, leading to some offsets
depending on what is shown on the line.

Thus, the LPM instruction has been replaced with an RJMP one, which,
instead, always takes 3 perfect cycles to be performed, timing is
not disrupted anymore, and image appears ok.
2021-08-11 11:24:41 +02:00
eaef011cbd generates an hardwired test pattern
This does not work as expected, and I don't understand why.
Clock cycle count seems ok, but if there are no changes in the pixels,
it seems to go faster
2021-08-11 09:04:59 +02:00
5bb884c502 hardwired jump table
This makes the microcontroller very application dependent,
but may save use some headaches.
The idea is to write a program to produce the code to show a
complex drawing.
2021-08-10 09:26:51 +02:00
53da6b7171 an hardcoded demo
prints "RE", a vertical line, and a counter
2021-07-03 16:42:32 +02:00
1764a5f2b3 line buffer dynamic update 2021-07-03 15:44:01 +02:00
9eaf78d6b5 introduced line buffer of 160 pixel 2021-07-03 15:02:01 +02:00
77b1858311 using a prescaler (eg /64) may lead to horizontal offset errors
because 1cycle off actually means many cycles off (eg 64)
2021-07-03 12:05:49 +02:00
2abac03779 semi working timer for skipping back porch 2021-07-03 11:54:31 +02:00
48da25958e back porch skipping, wasting clock cycles, basically 2021-06-28 21:54:25 +02:00
1f3f3f36f2 line, frame as words (16 bit) 2021-06-28 21:38:39 +02:00
0448c64be4 do nothing while not in interrupt 2021-06-27 23:08:47 +02:00
f3ce016a06 vertical line, scrolling from left to right
sufficiently handles the back/front porch without disrupting the sync
signal
todo improvement: compute a sensible amount of cycles to waste during
the porch
2021-06-27 22:37:11 +02:00
14fd0412d4 something strange is happening 2021-06-27 21:57:02 +02:00
97e0ff26fa "diagonal line"
not the whole screen, but vertically locked
actually it has some issues, there is a single dot (at the
end/beginning of a cycle) that messes up the horizontal sync and moves
all the picture... must be fixed
2021-06-26 23:42:23 +02:00
29990cd93a "diagonal line"
not vertically locked, just a test
also not the whole screen, just a bit
2021-06-26 22:34:22 +02:00
b7004a0171 first commit
vertical line at about 1/3 of the horizontal line
2021-06-26 19:15:17 +02:00