Dreamcast Output Interface¶

Emulates a Dreamcast controller connected via the Maple Bus protocol. Supports up to 4 players, analog triggers, and Puru Puru (rumble) feedback. Reports as a standard controller with vibration pack capability.

Protocol¶

Wire protocol: Maple Bus -- differential signaling on two data lines (SDCKA/SDCKB)
PIO program: maple.pio
Core: Core 1 handles real-time Maple Bus responses; Core 0 runs periodic maintenance via dreamcast_task()
Response delay: Minimum 50us before responding to console commands

The Dreamcast console sends command frames (device info, get condition, set condition). The adapter responds with appropriate device info or controller state. The adapter identifies as a standard controller (MAPLE_FT_CONTROLLER) with vibration pack support (MAPLE_FT_VIBRATION).

Maple Bus Commands Handled¶

Command	Code	Description
Device Info	`0x01`	Returns controller identity and function types
Extended Device Info	`0x02`	Returns extended device capabilities
Reset	`0x03`	Resets device state
Kill	`0x04`	Device shutdown
Get Condition	`0x09`	Poll controller state (buttons, sticks, triggers)
Set Condition	`0x0E`	Set peripheral settings (rumble motor commands)

GPIO Pins¶

Dreamcast Controller Connector Pinout¶

Looking at the controller plug (male, from controller cable):

     ___
   /  5  \
  | 4   3 |
  | 2   1 |
   \_____/

Pin	Signal	Description
1	SDCKA	Data line A
2	GND (Sense)	Ground / device detect
3	+5V	Power
4	GND	Ground
5	SDCKB	Data line B

KB2040 (default):

Signal	GPIO	Dreamcast Pin
SDCKA (Data Line A)	GP2	Pin 1
SDCKB (Data Line B)	GP3	Pin 5

RP2040-Zero (USB4Maple-compatible):

Signal	GPIO	Dreamcast Pin
SDCKA	GP14	Pin 1
SDCKB	GP15	Pin 5

Player Support¶

Max players: 4
Addressing: Each port addressed via Maple Bus port bits (0-3) in the frame header
Player colors: Orange (P1), Blue (P2), Red (P3), Green (P4)

Button Mapping¶

Dreamcast buttons are active-low in hardware (0 = pressed), handled internally by the driver.

JP_BUTTON_*	DC Button	Notes
`JP_BUTTON_B1`	A	Bottom face button
`JP_BUTTON_B2`	B	Right face button
`JP_BUTTON_B3`	X	Left face button
`JP_BUTTON_B4`	Y	Top face button
`JP_BUTTON_L1`	L Trigger (digital)	Left shoulder
`JP_BUTTON_R1`	R Trigger (digital)	Right shoulder
`JP_BUTTON_L2`	D button	Distinct from L, useful for N64-to-DC
`JP_BUTTON_R2`	R Trigger (analog)	Analog trigger
`JP_BUTTON_L3`	Z	Extra face button
`JP_BUTTON_R3`	C	Extra face button
`JP_BUTTON_S1`	D (2nd Start)	Arcade stick second start
`JP_BUTTON_S2`	Start	Start button
`JP_BUTTON_A1`	Start	Guide/Home also maps to Start
`JP_BUTTON_DU/DD/DL/DR`	D-pad	Direct mapping

Analog Mapping¶

Input	DC Output	Range
Left stick X	`joy_x`	0-255, 128 = center
Left stick Y	`joy_y`	0-255, 128 = center
Right stick X	`joy2_x`	0-255, 128 = center (extended controllers)
Right stick Y	`joy2_y`	0-255, 128 = center (extended controllers)
L2 analog	`lt`	0 = released, 255 = full
R2 analog	`rt`	0 = released, 255 = full

Feedback¶

Rumble (Puru Puru Pack)¶

The Dreamcast sends vibration commands via MAPLE_CMD_SET_CONDITION on the vibration function type. The adapter extracts:

Power (0-7): Vibration intensity
Frequency: Motor oscillation rate
Increment: Power ramp direction

The driver converts the power level to a 0-255 rumble value routed to the input controller's vibration motor via the player manager. Detailed motor parameters are available through dreamcast_get_purupuru_state().

Profiles¶

Profile support is available at the app level. The Dreamcast output does not define console-specific profiles.

Apps Using This Output¶

App	Description
`usb2dc`	USB/BT controllers to Dreamcast
`n642dc`	N64 controllers to Dreamcast