Rainbow Electronics HD44780 - Manual (Page 19)

HD44780U
19
Table 5 Relationship between CGRAM Addresses, Character Codes (DDRAM) and Character
Patterns (CGRAM Data)
Character Codes
(DDRAM data)
CGRAM Address
Character Patterns
(CGRAM data)
7 6 5 4 3 2 1 0
0 0 0 0 * 0 0 0
0 0 0 0 * 0 0 1
0 0 0 0 * 1 1 1
5 4 3 2 1 0
0 0 0
0 0 1
1 1 1
7 6 5 4 3 2 1 0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
High Low High Low High Low
Character
pattern (1)
Cursor position
1
1
1
1
1
1
1
0
1
0
1
0
1
0
0
0
0
1
1
0
0
0
1
0
1
0
1
0
1
0
0
0
1
0
0
1
0
0
0
0
0
1
1
0
1
0
0
0
1
0
0
1
1
0
0
0
0
0
1
1
1
1
1
0
1
0
0
1
0
1
0
0
0
1
1
0
1
0
0
0
Character
pattern (2)
Cursor position
For 5
×
8 dot character patterns
Notes: 1. Character code bits 0 to 2 correspond to CGRAM address bits 3 to 5 (3 bits: 8 types).
2. CGRAM address bits 0 to 2 designate the character pattern line position. The 8th line is the
cursor position and its display is formed by a logical OR with the cursor.
Maintain the 8th line data, corresponding to the cursor display position, at 0 as the cursor display.
If the 8th line data is 1, 1 bits will light up the 8th line regardless of the cursor presence.
3. Character pattern row positions correspond to CGRAM data bits 0 to 4 (bit 4 being at the left).
4. As shown Table 5, CGRAM character patterns are selected when character code bits 4 to 7 are
all 0. However, since character code bit 3 has no effect, the R display example above can be
selected by either character code 00H or 08H.
5. 1 for CGRAM data corresponds to display selection and 0 to non-selection.
* Indicates no effect.