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|
// license:BSD-3-Clause
// copyright-holders:Vas Crabb
/**********************************************************************
Dempa Micom Soft Analog/Digital Controller emulation
PC pin Name MD pin Name Dir Signal
1 Up 1 Up In D0
2 Down 2 Down In D1
3 Left 3 Left In D2
4 Right 4 Right In D3
6 TRIG1 6 TL In L/H
7 TRIG2 9 TR In ACK
8 STROBE 7 TH Out REQ
In analog mode, data is shifted out as twelve nybbles:
_ ________________________________________________________________
REQ \_________/
____ __ __ __ __ __ __ __ __ __ __ __ __
ACK \__/ \__/ \__/ \__/ \__/ \__/ \__/ \__/ \__/ \__/ \__/ \__/
_____ _____ _____ _____ _____ _____
L/H _______/ \_____/ \_____/ \_____/ \_____/ \_____/ \__
_____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____
D XXXX_____X_____X_____X_____X_____X_____X_____X_____X_____X_____X_____X_____X
The falling edge on REQ causes data output to start. The host
can't control the speed, it just polls the L/H and ACK lines to
know when the data is ready to read.
Nybble D3 D2 D1 D0
1 A/A' B/B' C D
2 E1 E2 Start Select
3 Y7 Y6 Y5 Y4
4 X7 X6 X5 X4
5 Z7 Z6 Z5 Z4
6 RZ7 RZ6 RZ5 RZ4
7 Y3 Y2 Y1 Y0
8 X3 X2 X1 X0
9 Z3 Z2 Z1 Z0
10 RZ3 RZ2 RZ1 RZ0
11 A B A' B'
12 - - - -
In MD mode, each pair of nybbles is transmitted in reverse
order.
Sharp released assembly language source code for an X68000
driver. It uses the following algorithm:
1. Generate falling edge on REQ
2. Wait until L/H is low
3. Wait until ACK is low
4. Read a nybble
5. Wait until L/H is high
6. Wait until ACK is low
7. Read a nybble
8. If eight nybbles have been read, raise REQ.
9. Loop to step 2 until twelve nybbles have been read
Mega Drive games use a similar approach, but raise REQ after
reading two nybbles. PC Engine games only generate a short low
pulse on REQ, but use the same algorithm to determine when to
read data.
CSK Research Institute games for FM Towns (including After
Burner III and Galaxy Force II) use a different algorithm:
1. Generate falling edge on REQ
2. Wait until L/H is high
3. Wait until ACK is high
4. Read a nybble
5. Wait until L/H is low
6. Wait until ACK is high
7. Read a nybble
8. Wait until L/H is high
9. Wait until ACK is high
10. Read a nybble
11. Loop to step 5 until eleven nybbles have been read
11. Raise REQ
From this it can be deduced that:
* A negative edge on REQ triggers a report.
* The exact time REQ is held low isn't important.
* Data is valid while ACK is low and for some time after ACK is
raised.
* L/H is low when idle and changes some time before data is
updated.
In digital mode, REQ is a simple multiplexer input:
REQ 0 1
D0 Up Throttle Up
D1 Down Throttle Down
D2 Left C
D3 Right D
L/H A/A' E1
ACK B/B' E2
Start appears as simultaneous Left/Right
Select appears as simultaneous Up/Down
This mode is almost compatible with a 6-button Towns Pad (on a
real 6-button Towns Pad, buttons A and B can be read in either
state, they bypass the multiplexer).
Digital MD mode emulates a 3-button Mega Drive pad:
REQ 0 1
D0 Up Up
D1 Down Down
D2 0 Left
D3 0 Right
L/H A B
ACK Start C
TODO:
* Dump MB88513 microcontroller from original controller.
* Measure timings.
- Timings currently fudged for CRI games in FM Towns.
* Latch data at beginning of packet.
* Confirm button mapping in digital mode.
* Estimate thresholds in digital modes.
* Implement trigger A/B rapid fire switches.
* Implement channel shift switch (Y->X, X->Z, Z->X).
* Does channel shift affect digital mode?
* Implement special modes (holding buttons on power-on):
- Double displacement modes:
+ X/Y (hold SELECT + A')
+ Z (hold SELECT + B')
+ X/Y/Z (hold SELECT + A' + B')
- Up/down reverse mode (hold C)
* Implement desktop (XE-1AJ/CZ-8NJ2) version:
- Four analog channels
- E1/E2 on a rocker switch (can't press simultaneously)
- Hold mode for A and B triggers
- Variable rapid fire rate for A and B triggers
- Reset button
- Different special modes
- No Mega Drive mode
- Start and Select not reported in digital mode
**********************************************************************/
#include "emu.h"
#include "micomxe1a.h"
//#define VERBOSE 1
//#define LOG_OUTPUT_FUNC osd_printf_info
#include "logmacro.h"
DEFINE_DEVICE_TYPE(MICOM_XE_1A, micom_xe_1a_device, "micom_xe_1a", "Dempa Micom Soft Analog/Digital Intelligent Controller")
micom_xe_1a_device::micom_xe_1a_device(
machine_config const &mconfig,
char const *tag,
device_t *owner,
u32 clock):
device_t(mconfig, MICOM_XE_1A, tag, owner, clock),
m_buttons_callback(*this, 0xffff),
m_analog_callback(*this, 0x00),
m_output_timer(nullptr),
m_req(1),
m_mode(1),
m_interface(0),
m_out(0x2f)
{
}
micom_xe_1a_device::~micom_xe_1a_device()
{
}
u8 micom_xe_1a_device::out_r()
{
if (m_mode)
{
LOG("%s: analog mode read data = %02X\n", machine().describe_context(), m_out);
return m_out;
}
else
{
u16 const buttons = m_buttons_callback();
if (m_interface)
{
u8 const y = m_analog_callback(0);
if (m_req)
{
u8 const x = m_analog_callback(1);
u8 const result =
((0x40 <= y) ? 0x01 : 0x00) | // Up
((0xc0 > y) ? 0x02 : 0x00) | // Down
((0x40 <= x) ? 0x04 : 0x00) | // Left
((0xc0 > x) ? 0x08 : 0x00) | // Right
((BIT(buttons, 2) & BIT(buttons, 8)) << 4) | // B/B'
(BIT(buttons, 1) << 5); // C
LOG(
"%s: MD digital mode basic read = 0x%02X\n",
machine().describe_context(),
result);
return result;
}
else
{
u8 const result =
((0x40 <= y) ? 0x01 : 0x00) | // Up
((0xc0 > y) ? 0x02 : 0x00) | // Down
((BIT(buttons, 3) & BIT(buttons, 9)) << 4) | // A/A'
(BIT(buttons, 5) << 5); // Start
LOG(
"%s: MD digital mode extended read = 0x%02X\n",
machine().describe_context(),
result);
return result;
}
}
else
{
if (m_req)
{
u8 const z = m_analog_callback(2);
u8 const result =
((0x40 <= z) ? 0x01 : 0x00) | // Throttle Up
((0xc0 > z) ? 0x02 : 0x00) | // Throttle Down
(BIT(buttons, 1) << 2) | // C
(BIT(buttons, 0) << 3) | // D
(BIT(buttons, 7) << 4) | // E1
(BIT(buttons, 6) << 5); // E2
LOG(
"%s: digital mode extended read = 0x%02X\n",
machine().describe_context(),
result);
return result;
}
else
{
u8 const y = m_analog_callback(0);
u8 const x = m_analog_callback(1);
u8 const result =
((BIT(buttons, 4) && (0x40 <= y)) ? 0x01 : 0x00) | // Select/Up
((BIT(buttons, 4) && (0xc0 > y)) ? 0x02 : 0x00) | // Select/Down
((BIT(buttons, 5) && (0x40 <= x)) ? 0x04 : 0x00) | // Start/Left
((BIT(buttons, 5) && (0xc0 > x)) ? 0x08 : 0x00) | // Start/Right
((BIT(buttons, 3) & BIT(buttons, 9)) << 4) | // A/A'
((BIT(buttons, 2) & BIT(buttons, 8)) << 5); // B/B'
LOG(
"%s: digital mode basic read = 0x%02X\n",
machine().describe_context(),
result);
return result;
}
}
}
}
void micom_xe_1a_device::req_w(int state)
{
u8 const req = state ? 1 : 0;
if (req != m_req)
{
if (m_mode)
{
LOG("%s: /REQ = %u\n", machine().describe_context(), req);
if (!req)
{
// acquire data
u16 const buttons = m_buttons_callback();
u8 analog[4];
for (unsigned i = 0; std::size(analog) > i; ++i)
analog[i] = m_analog_callback(i);
// pack data
m_data[0] = BIT(buttons, 0, 8) & ((BIT(buttons, 8, 2) << 2) | 0xf3);
m_data[1] = BIT(analog[0], 4, 4) | (BIT(analog[1], 4, 4) << 4);
m_data[2] = BIT(analog[2], 4, 4) | (BIT(analog[3], 4, 4) << 4);
m_data[3] = BIT(analog[0], 0, 4) | (BIT(analog[1], 0, 4) << 4);
m_data[4] = BIT(analog[2], 0, 4) | (BIT(analog[3], 0, 4) << 4);
m_data[5] = BIT(buttons, 8, 8) & ((BIT(buttons, 2, 2) << 2) | 0xf3);
// takes a while to respond
m_output_timer->adjust(attotime::from_nsec(50'000), 0);
}
}
else
{
LOG("%s: /REQ = %u ignored in digital mode\n", machine().describe_context(), req);
}
m_req = req;
}
}
void micom_xe_1a_device::mode_w(int state)
{
u8 const mode = state ? 1 : 0;
if (mode != m_mode)
{
if (mode)
{
LOG("Analog mode selected\n");
}
else
{
LOG("Digital mode selected\n");
m_output_timer->enable(false);
m_out = 0x2f;
}
m_mode = mode;
}
}
void micom_xe_1a_device::interface_w(int state)
{
m_interface = state ? 1 : 0;
}
void micom_xe_1a_device::device_start()
{
m_output_timer = timer_alloc(FUNC(micom_xe_1a_device::step_output), this);
std::fill(std::begin(m_data), std::end(m_data), 0x00);
m_out = 0x2f;
save_item(NAME(m_req));
save_item(NAME(m_mode));
save_item(NAME(m_interface));
save_item(NAME(m_data));
save_item(NAME(m_out));
}
TIMER_CALLBACK_MEMBER(micom_xe_1a_device::step_output)
{
auto const step = param >> 1;
if (!BIT(param, 0))
{
m_out = (m_out & 0x0f) | (BIT(step, 0) ? 0x30 : 0x20);
LOG(
"Set nybble %u data = 0x%X, L/H = %u, /ACK = %u\n",
step,
BIT(m_out, 0, 4),
BIT(m_out, 4),
BIT(m_out, 5));
if ((std::size(m_data) * 2) > step)
{
m_output_timer->adjust(attotime::from_nsec(10'000), param + 1);
}
}
else
{
if ((std::size(m_data) * 2) > step)
{
auto const nybble = step ^ m_interface;
if ((std::size(m_data) * 2) > step)
m_out = BIT(m_data[nybble >> 1], BIT(nybble, 0) ? 4 : 0, 4) | (m_out & 0x10);
else
m_out = 0x0f | (m_out & 0x10);
LOG(
"Set nybble %u data = 0x%X, L/H = %u, /ACK = %u\n",
step,
BIT(m_out, 0, 4),
BIT(m_out, 4),
BIT(m_out, 5));
m_output_timer->adjust(attotime::from_nsec(10'000), param + 1);
}
}
}
|