Looking for sources MSX2+ / MSX-tr boot logo routine

By Accumulator

Resident (53)

Accumulator's picture

02-05-2022, 12:08

I am looking for sources of boot logo routine of MSX2+ / Tr.
I do not care if it is reversed engineered or original sources.
Reason is to understand the registers and ports, screens, timings of v9958 and routine without getting the R26/R27 line interrupt noise at boot logo when logo get merged from left and right.
I have not tested yet, but is the noise not visible in screen6/7?

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By Sylvester

Hero (568)

Sylvester's picture

02-05-2022, 12:36

Check this repo: https://sourceforge.net/p/msxsyssrc/git/ci/master/tree/ it contains the reversed engineered sources of a lot of MSX ROMS (Base300 is MSX2+ and Base410 is TR)

By Accumulator

Resident (53)

Accumulator's picture

04-05-2022, 15:05

Thanks, I have looked in the option rom filees and noticed the vdp register remarks.
The notification of amount of Ram/VideoRam is not mentioned in the code.
The option rom I have disassembled as well and could not find explanations.

I hope someone has the code including text labels, readable ports (subtracted 128 and +), etc.
I am not lazy, but like to read it and understand as a manual

By Accumulator

Resident (53)

Accumulator's picture

03-09-2022, 07:03

Thanks Sylvester,

Checked the sources and understanding line by line,
I just wanted to know whether the 9958 VDP HAD a noise problem with R26 & R27.
Even in the boot sequence there is a noise at approx 1/3 of the screen..

Thanks for sharing those resurces