====== DNS-323 GPIO Mapping ======

The following information was deduced by reading the D-Link supplied DNS323 2.6.12.6 kernel source together with empirical reverse engineering.

^ GPIO Pin # ^ GPIO Mask ^ Direction ^ Purpose ^
| 0  | ''0x0001''  | Input  | //unknown// |
| 1  | ''0x0002''  | Output | right amber LED (= sata ch0 LED)  (low-active) |
| 2  | ''0x0004''  | Output | left  amber LED (= sata ch1 LED)  (low-active) |
| 3  | ''0x0008''  | Output | //unknown// |
| 4  | ''0x0010''  | Output | power button LED (low-active, together with pin #5) |
| 5  | ''0x0020''  | Output | power button LED (low-active, together with pin #4) |
| 6  | ''0x0040''  | Input | //unknown// |
| 7  | ''0x0080''  | Input | //unknown// |
| 8  | ''0x0100''  | Output | triggers power off (high-active) |
| 9  | ''0x0200''  | Input | power button switch (low-active) |
| 10 | ''0x0400''  | Input | reset button switch (low-active) |
| 11 | ''0x0800''  | Output | //unknown// |
| 12 | ''0x1000''  | Output | //unknown// |
| 13 | ''0x2000''  | Output | //unknown// |
| 14 | ''0x4000''  | Output | //unknown - maybe sata ch0 blue LED// |
| 15 | ''0x8000''  | Output | //unknown - maybe sata ch1 blue LED// |
| 16-31 ||| //unknown - nothing expected// |

DNS323 rev.C1 has new system board and different MPP/GPIO wiring.

^GPIO Pin # ^ Direction ^ Purpose ^
|0 | Input | Not connected |
|1 | Input | Power Key Out |
|2 | Output | Power Control |
|3 | Input | AC Power Loss |
|4 | Input | Not connected |
|5 | Input | Not connected |
|6 | Input | Not connected |
|7 | Input | USB Controller Fault |
|8 | Input | HDD0 Error |
|9 | Input | HDD1 Error |
|10 | Input | Reset button |
|11 | Output | Power LED Green |
|12 | Output | HDD0 Link |
|13 | Output | HDD1 Link |
|14 | Output | HDD0 Act |
|15 | Output | HDD1 Act |
|16 | Output | Power LED Red |
|17 | Output | Power LED Blue |
|18 | Output | Fan Control (FULL Speed) |
|19 | Output | Fan Control (HALF Speed) |
|20 | Input | Not connected |
|21 | Input | Not connected |
|22 | Input | Fan Status |
|23 | Input | Unknown |
|24 | Input | Thermal Interrupt |
|25 | Input | RTC Interrupt |