Instruction Set
The HD44780 instruction set is shown below:
| Instruction | Code | Description | Execution time (max) (when fcp = 270 kHz) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| RS | R/W | B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 | |||
| Clear display | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | Clears display and returns cursor to the home position (address 0). | 1.52 ms |
| Cursor home | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | * | Returns cursor to home position. Also returns display being shifted to the original position. DDRAM content remains unchanged. | 1.52 ms |
| Entry mode set | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | I/D | S | Sets cursor move direction (I/D); specifies to shift the display (S). These operations are performed during data read/write. | 37 μs |
| Display on/off control | 0 | 0 | 0 | 0 | 0 | 0 | 1 | D | C | B | Sets on/off of all display (D), cursor on/off (C), and blink of cursor position character (B). | 37 μs |
| Cursor/display shift | 0 | 0 | 0 | 0 | 0 | 1 | S/C | R/L | * | * | Sets cursor-move or display-shift (S/C), shift direction (R/L). DDRAM content remains unchanged. | 37 μs |
| Function set | 0 | 0 | 0 | 0 | 1 | DL | N | F | * | * | Sets interface data length (DL), number of display line (N), and character font (F). | 37 μs |
| Set CGRAM address | 0 | 0 | 0 | 1 | CGRAM address | Sets the CGRAM address. CGRAM data are sent and received after this setting. | 37 μs | |||||
| Set DDRAM address | 0 | 0 | 1 | DDRAM address | Sets the DDRAM address. DDRAM data are sent and received after this setting. | 37 μs | ||||||
| Read busy flag & address counter |
0 | 1 | BF | CGRAM/DDRAM address | Reads busy flag (BF) indicating internal operation being performed and reads CGRAM or DDRAM address counter contents (depending on previous instruction). | 0 μs | ||||||
| Write CGRAM or DDRAM |
1 | 0 | Write Data | Write data to CGRAM or DDRAM. | 37 μs | |||||||
| Read from CG/DDRAM | 1 | 1 | Read Data | Read data from CGRAM or DDRAM. | 37 μs | |||||||
| Instruction bit names — I/D - 0 = decrement cursor position, 1 = increment cursor position; S - 0 = no display shift, 1 = display shift; D - 0 = display off, 1 = display on; C - 0 = cursor off, 1 = cursor on; B - 0 = cursor blink off, 1 = cursor blink on ; S/C - 0 = move cursor, 1 = shift display; R/L - 0 = shift left, 1 = shift right; DL - 0 = 4-bit interface, 1 = 8-bit interface; N - 0 = 1/8 or 1/11 duty (1 line), 1 = 1/16 duty (2 lines); F - 0 = 5×8 dots, 1 = 5×10 dots; BF - 0 = can accept instruction, 1 = internal operation in progress. |
||||||||||||
Read more about this topic: Hitachi HD44780 LCD Controller
Famous quotes containing the words instruction and/or set:
“I have come to believe ... that the stage may do more than teach, that much of our current moral instruction will not endure the test of being cast into a lifelike mold, and when presented in dramatic form will reveal itself as platitudinous and effete. That which may have sounded like righteous teaching when it was remote and wordy will be challenged afresh when it is obliged to simulate life itself.”
—Jane Addams (1860–1935)
“With all her masculine vigour and glory, Greece fell, gradually atrophied, because one half of her had been, of set purpose, intellectually and politically paralyzed.”
—Tennessee Claflin (1846–1923)