Sticky — Input Controller
A 5V-tolerant AVR microcontroller dedicated to safe, reliable classic joystick and controller interfacing.
Overview
| Feature | Prototype | Final |
|---|---|---|
| Chip | AVR128DB48 | AVR128DB64 |
| Clock | 16MHz | 24MHz |
| Dev kit | Curiosity Nano (on Nano Base) | — |
| Flash | 128KB | 128KB |
| SRAM | 16KB | 16KB |
| EEPROM | 512 bytes | 512 bytes |
| User row | 32 bytes | 32 bytes |
| Programming | Single-wire UPDI | Single-wire UPDI |
Controller Ports
4× Atari/Sega DB9 joystick ports at the front of the computer, supporting:
- 6-button Sega sticks
- Analog paddles
- 9-pin mice
- Port A can be configured as I2C (pins 3 and 4)
- Each port can be configured for serial TX/RX (pins 6 and 7)
Curiosity Nano Pinout
| Description | Function | Pin | Pin | Function | Description |
|---|---|---|---|---|---|
| NC | NC | 1 | 29 | VBUS | — |
| — | ID | 2 | 30 | VOFF | GND |
| NC | B0 | 3 | 31 | F6 | RESET |
| NC | B1 | 4 | 32 | UPDI | DEBUG |
| Yellow LED | B2 | 5 | 33 | GND | GND |
| Button | B3 | 6 | 34 | VTG | 5V |
| DB9-D3 | F4 | 7 | 35 | D6 | DB9-D5 |
| DB9-D4 | F5 | 8 | 36 | D3 | DB9-B9 |
| DB9-A1 | A2 | 9 | 37 | D2 | DB9-B5 |
| DB9-A2 | A3 | 10 | 38 | D1 | DB9-A9 |
| DB9-A3 | A4 | 11 | 39 | D0 | DB9-A5 |
| DB9-A4 | A5 | 12 | 40 | D7 | DB9-D9 |
| DB9-A6 | A6 | 13 | 41 | D5 | DB9-C9 |
| DB9-A7 | A7 | 14 | 42 | D4 | DB9-C5 |
| GND | GND | 15 | 43 | GND | GND |
| DB9-B6 | B0 | 16 | 44 | E3 | SPI0-SEL |
| DB9-B7 | B1 | 17 | 45 | E2 | SPI0-SCK |
| DB9-D1 | F2 | 18 | 46 | E1 | SPI0-MISO |
| DB9-D2 | F3 | 19 | 47 | E0 | SPI0-MOSI |
| DB9-C6 | C0 | 20 | 48 | C7 | DB9-C5 via 2N2222 |
| DB9-C7 | C1 | 21 | 49 | C6 | SPI0 INT-OUT |
| DB9-C1 | C2 | 22 | 50 | C5 | DB9-C4 |
| DB9-C2 | C3 | 23 | 51 | C4 | DB9-C3 |
| GND | GND | 24 | 52 | GND | GND |
| 16MHz IN | A0 | 25 | 53 | B5 | DB9-B5 |
| 16MHz OUT | A1 | 26 | 54 | B4 | DB9-B4 |
| DB9-B1 | B2 | 27 | 55 | F1 CUT J208 | DB9-D7 |
| DB9-B2 | B3 | 28 | 56 | F0 CUT J207 | DB9-D6 |
Programming
Sticky is UPDI-programmed. In the prototype that's done from the Curiosity Nano's built-in UPDI debugger over USB. In the final production system the UPDI line is wired to Pulse, which performs the bit-bang under orchestration from DeMon:
- DeMon holds the firmware files (in DBFS), parses them, and sends the program bytes plus fuse settings over the bidirectional SPI peer link to Pulse
- Pulse buffers the image in PSRAM, parks any active sequencer work, runs the UPDI session against Sticky, verifies the readback, and reports status back to DeMon
- The user-facing entry point is the AntOS
update stickycommand
UPDI is used for firmware update and possible debug only. Normal joystick / paddle / mouse data flows over the SPI peer link from Sticky to Pulse, separately. See DeMon UPDI Orchestration and Pulse UPDI service for the full picture.