vcs_ctrl: Add support for Atari CX22/CX80 Trak-Ball in native trackball mode (#12722)

scripts/src/bus.lua

@@ -2701,6 +2701,8 @@ if (BUSES["VCS_CTRL"]~=null) then
 		MAME_DIR .. "src/devices/bus/vcs_ctrl/mouse.h",
 		MAME_DIR .. "src/devices/bus/vcs_ctrl/paddles.cpp",
 		MAME_DIR .. "src/devices/bus/vcs_ctrl/paddles.h",
+		MAME_DIR .. "src/devices/bus/vcs_ctrl/trakball.cpp",
+		MAME_DIR .. "src/devices/bus/vcs_ctrl/trakball.h",
 		MAME_DIR .. "src/devices/bus/vcs_ctrl/wheel.cpp",
 		MAME_DIR .. "src/devices/bus/vcs_ctrl/wheel.h",
 	}

src/devices/bus/vcs_ctrl/ctrl.cpp

@@ -72,6 +72,7 @@ void vcs_control_port_device::device_start()
 #include "lightpen.h"
 #include "mouse.h"
 #include "paddles.h"
+#include "trakball.h"
 #include "wheel.h"
 
 void vcs_control_port_devices(device_slot_interface &device)
@@ -84,6 +85,7 @@ void vcs_control_port_devices(device_slot_interface &device)
 	device.option_add("wheel", VCS_WHEEL);
 	device.option_add("keypad", VCS_KEYPAD);
 	device.option_add("cx85", ATARI_CX85);
+	device.option_add("trakball", ATARI_TRAKBALL);
 }
 
 void a800_control_port_devices(device_slot_interface &device)

src/devices/bus/vcs_ctrl/trakball.cpp

@@ -0,0 +1,148 @@
+// license:BSD-3-Clause
+/**********************************************************************
+
+    Atari CX22/CX80 Trak-Ball
+
+Note: this module only works in trackball mode and not in joystick emulation mode
+
+Reference: Atari, CX22 Trakball Field Service Manual, Rev. 01 (FD100660), November 1983
+
+**********************************************************************/
+
+#include "emu.h"
+#include "trakball.h"
+
+/***************************************************************************
+    CONSTANTS
+***************************************************************************/
+
+#define TRAKBALL_BUTTON_TAG "trackball_buttons"
+#define TRAKBALL_XAXIS_TAG  "trackball_x"
+#define TRAKBALL_YAXIS_TAG  "trackball_y"
+
+#define TRAKBALL_POS_UNINIT 0xffffffff /* default out-of-range position */
+
+//**************************************************************************
+//  DEVICE TYPE DEFINITION
+//**************************************************************************
+
+DEFINE_DEVICE_TYPE(ATARI_TRAKBALL, atari_trakball_device, "atari_trakball", "Atari CX22/CX80 Trak-Ball")
+
+
+//**************************************************************************
+//  INPUT PORTS
+//**************************************************************************
+
+static INPUT_PORTS_START(atari_trakball)
+	PORT_START(TRAKBALL_BUTTON_TAG) /* Trak-ball - button */
+	PORT_BIT( 0x0f, IP_ACTIVE_HIGH, IPT_UNUSED )
+	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON1) PORT_WRITE_LINE_MEMBER(atari_trakball_device, trigger_w)
+	PORT_BIT( 0xd0, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START(TRAKBALL_XAXIS_TAG) /* Trak-ball - X AXIS */
+	PORT_BIT( 0xff, 0x00, IPT_TRACKBALL_X) PORT_SENSITIVITY(80) PORT_KEYDELTA(0) PORT_PLAYER(1) PORT_CHANGED_MEMBER(DEVICE_SELF, atari_trakball_device, trakball_moved, 0)
+
+	PORT_START(TRAKBALL_YAXIS_TAG) /* Trak-ball - Y AXIS */
+	PORT_BIT( 0xff, 0x00, IPT_TRACKBALL_Y) PORT_SENSITIVITY(80) PORT_KEYDELTA(0) PORT_PLAYER(1) PORT_CHANGED_MEMBER(DEVICE_SELF, atari_trakball_device, trakball_moved, 1)
+INPUT_PORTS_END
+
+
+//**************************************************************************
+//  LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+//  atari_cx85_device - constructor
+//-------------------------------------------------
+
+atari_trakball_device::atari_trakball_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: device_t(mconfig, ATARI_TRAKBALL, tag, owner, clock)
+	, device_vcs_control_port_interface(mconfig, *this)
+	, m_trakballb(*this, TRAKBALL_BUTTON_TAG)
+	, m_trakballxy(*this, { TRAKBALL_XAXIS_TAG, TRAKBALL_YAXIS_TAG })
+	, m_last_pos{ TRAKBALL_POS_UNINIT, TRAKBALL_POS_UNINIT }
+	, m_last_direction{ 0, 0 }
+{
+}
+
+//-------------------------------------------------
+//  device_input_ports - device-specific input ports
+//-------------------------------------------------
+
+ioport_constructor atari_trakball_device::device_input_ports() const
+{
+	return INPUT_PORTS_NAME(atari_trakball);
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void atari_trakball_device::device_start()
+{
+}
+
+#define QUADRATURE_ANGLE_RESOLUTION 0x02
+
+//-----------------------------------------------------------------
+//  trakbal_pos_and_dir_upd - update tracked position and direction
+//-----------------------------------------------------------------
+
+void atari_trakball_device::trakball_pos_and_dir_upd(int axis)
+{
+	int diff_pos = 0;
+	int cur_pos = 0;
+
+	cur_pos = m_trakballxy[axis]->read();
+	if (m_last_pos[axis] == TRAKBALL_POS_UNINIT) {
+		if (!machine().side_effects_disabled()) {
+			m_last_pos[axis] = cur_pos;
+		}
+	}
+	diff_pos = cur_pos - m_last_pos[axis];
+	// wrap-around the position
+	if (diff_pos > 0x7f) {
+		diff_pos -= 0x100;
+	} else if (diff_pos < -0x80) {
+		diff_pos += 0x100;
+	}
+	if (!machine().side_effects_disabled()) {
+		m_last_pos[axis] = cur_pos;
+		if (diff_pos) {
+			m_last_direction[axis] = diff_pos > 0;
+		}
+	}
+}
+
+//---------------------------------------------------------
+//  trakball_moved - called when moved outside of polling
+//---------------------------------------------------------
+
+INPUT_CHANGED_MEMBER( atari_trakball_device::trakball_moved )
+{
+	const int axis(param);
+
+	trakball_pos_and_dir_upd(axis);
+}
+
+//-------------------------------------------------
+//  vcs_joy_r - read digital inputs
+//-------------------------------------------------
+
+u8 atari_trakball_device::vcs_joy_r()
+{
+	u8 vcs_joy_return = 0;
+
+	for (int axis = 0; axis < 2; axis++) {
+		trakball_pos_and_dir_upd(axis);
+	}
+
+	vcs_joy_return =
+		m_trakballb->read() |
+		(m_last_direction[0] ? 0x01 : 0x00) |
+		((m_last_pos[0] & QUADRATURE_ANGLE_RESOLUTION) ? 0x02 : 0x00) |
+		(m_last_direction[1] ? 0x04 : 0x00) |
+		((m_last_pos[1] & QUADRATURE_ANGLE_RESOLUTION) ? 0x08 : 0x00);
+
+	return vcs_joy_return;
+}

src/devices/bus/vcs_ctrl/trakball.h

@@ -0,0 +1,53 @@
+// license:BSD-3-Clause
+/**********************************************************************
+
+    Atari CX22/CX80 Trak-Ball
+
+**********************************************************************/
+
+#ifndef MAME_BUS_VCS_CTRL_TRAKBALL_H
+#define MAME_BUS_VCS_CTRL_TRAKBALL_H
+
+#pragma once
+
+#include "ctrl.h"
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> atari_trakball_device
+
+class atari_trakball_device : public device_t,
+							public device_vcs_control_port_interface
+{
+public:
+	// construction/destruction
+	atari_trakball_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+	DECLARE_INPUT_CHANGED_MEMBER( trakball_moved );
+
+protected:
+	// device_t implementation
+	virtual void device_start() override;
+
+	// optional information overrides
+	virtual ioport_constructor device_input_ports() const override;
+
+	// device_vcs_control_port_interface overrides
+	virtual u8 vcs_joy_r() override;
+
+private:
+	required_ioport m_trakballb;
+	required_ioport_array<2> m_trakballxy;
+
+	void trakball_pos_and_dir_upd(int axis);
+
+	uint32_t m_last_pos[2];
+	uint8_t m_last_direction[2];
+};
+
+
+// device type declaration
+DECLARE_DEVICE_TYPE(ATARI_TRAKBALL, atari_trakball_device)
+
+#endif // MAME_BUS_VCS_CTRL_TRAKBALL_H