Board 50227
Seems similar to the 50229 board, but other display type (DLO1414 vs PD4435), other MCU (atmega161 where 50229 has a '162), and more buttons.
Seems like we have just 1 of this board. It might be similar to Bestand:IMG_8958.jpeg which then would be a second one.
buttons
4 extra buttons; wired between row 0/1, row 1/2 and col 1/2, col 2/3.
display mapping
6 displays (DLO1414) - mapped per below; with from left to right in each screen '3210'.
Displays zitten aangesloten volgens het voorbeeld uit de datasheet, op de 74HC138 rechtsboven de atmega161.
Echter, er worden meer enable-pinnen gebruikt dan in het voorbeeld schema. Zie onderstaande tabel. Tussen haakjes de namen uit de 74HC138 datasheet achter de namen uit het voorbeeldschema.
Atmega161 | 74hc138 |
---|---|
pin 24 PC3 | A (A0) |
pin 25 PC4 | B (A1) |
pin 26 PC5 | C (A2) |
pin 27 PC6 | G (E3) |
pin 28 PC7 | (nE1) |
pin 16 PD6 nWR | (nE2) |
De datalijnen D0-D6 zitten op PA0-PA6 van de atmega161 (pin 39 PA0 tot pin 33 PA6). Er is bij dit type display geen D7.
reading the buttons
The 21 buttons are mostly in a 4x4 matrix. Every switch is between two MCU pins. The pins not fitting in the matrix are between 2 rows or 2 collumns.
The buttons 1, 2, 3 on the left are named 1, 2, 3 in the tables as well. The buttons labeled 1, 2, 3 on the right are labeled 1' 2' 3' as these are not in parallel with the others labeled 1, 2, 3.
row/col | PD2 | PD3 | PD4 | PD5 |
PB3 | 36C | 2' | 3 | 04 |
PB2 | 24 | 18C | 1 | 2 |
PB1 | 27 | 36R | 36L | 1' |
PB0 | HELI | 09 | 18L | 18R |
The keys that are between 2 row lines or between 2 collumn lines can be re-fitted in another matrix: (Possibly other configurations are possible and maybe even more efficient! By choosing other row/col lines in software for the same hardware)
row/col | PD5 | PB2 | PD3 | PB0 |
PD4 | 3' | . | EXEC | . |
PB3 | . | CORR | . | . |
PB1 | . | 22 | . | 06 |
The keys are thus NOT the same als on 50229.
Read as any other keyboard matrix (? Enable pull-ups on input row/col s & unused col/row and drive one col/row low ?)
LEDS
Todo! (Might be different from 50229 also... Though same circuit with a 74hc138 and 74hc174 seems to have been applied, it might be connected to different IO lines compared to 50229... )