SeekFrom::Line does not make sense for CGRAM

[kunerd]

CGRAM has different size than DDRAM.

CGRAM = 64 byte DDRAM = 128 byte (2 line version)

[kunerd]

CGRAM is devided into two address rooms, the first one for characters itself and the other for each pixel line of a character. See Table 5, Datasheet page 19-20.

5x8 dot characters:

7	6	5 \	4 \	3	2 \	1 \	0
r	r	char addr	line addr

• r.. reserved
• char addr -> 0..7 -> 8 custom characters
• line addr -> 0..7 -> 8 lines per character

5x10 dot characters:

7	6	5 \	4	3 \	2 \	1 \	0
r	r	char addr	line addr

• r.. reserved
• char addr -> 0..3 -> 4 custom characters
• line addr -> 0..15 -> 16 lines per character (only 11 are used)

[kunerd]

Implementation proposal:

pub struct CharacterAddress(u8);
pub struct CharacterLineAddress(u8);

pub enum SeekCgRamFrom<T> {
    Home(T),
    Current(T),
}

impl<P, U> Display<P, U, CgRam>
where
    U: Into<Address> + Home,
    P: Send,
{
    pub fn seek_character(&self, pos: SeekCgRamFrom<CharacterAddress>) {
        // ...
    }
    pub fn seek_character_line(
        &self,
        char_pos: SeekCgRamFrom<CharacterAddress>,
        line_pos: SeekCgRamFrom<CharacterLineAddress>,
    ) {
        // ...
    }
    // ...
}

[kunerd]

fixed by #29