What was really cool about the TRS-80 is that the graphics were really represented as a custom character encoding. The screen was 64 cols and 16 rows. Exactly

What was really cool about the TRS-80 is that the graphics were really represented as a custom character encoding. The screen was 64 cols and 16 rows. Exactly 1 kB. And as you said, each character could show either the lower 127 aasci character with decent resolution, or the character could be broken up into 2x3 graphics, represented as 64 bits of the upper non-ascii character byte. So text and graphics were easily mixed and looked good. You could even peek and poke directly into the screen memory locationand immediately display any graphics or text. I made a cool drawing program that saved pictures by basically scanning the screen memory and capturing the 1024 unique bytes that determined what was being displayed (graphics and/or text) and saved to disk.