please confirm my understanding of screen memory map is right.

[social_loser]

I read the screen specification in Figure 5.4.   if I got it correctly, if you want to make a  screen "byte" looks like ( B stands for black , which is true bit, W for white):

BBBBBWWWWWWWWWWW

you actually have to write the  16-bit  binary value as :

0000000000011111

instead of 1111100000000000 , right ?

[cadet1620]

You can confirm this yourself using the CPUEmulator.

Write the value 31 into RAM address 16384.

--Mark

[social_loser]

thank you for the tip, I got it now.