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// license: BSD-3-Clause
// copyright-holders: Dirk Best
/***************************************************************************
µPD7004
10-bit 8 Channel A/D Converter
TODO:
- Serial modes
- 2s complement output
***************************************************************************/
#include "emu.h"
#include "upd7004.h"
#define VERBOSE 0
#include "logmacro.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(UPD7004, upd7004_device, "upd7004", "UPD7004 A/D Converter")
// permit our enum to be saved
ALLOW_SAVE_TYPE(upd7004_device::state);
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// upd7004_device - constructor
//-------------------------------------------------
upd7004_device::upd7004_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
device_t(mconfig, UPD7004, tag, owner, clock),
m_eoc_cb(*this), m_eoc_ff_cb(*this),
m_in_cb(*this),
m_state(STATE_IDLE),
m_cycle_timer(nullptr),
m_div(1), m_code(false), m_address(0), m_sar(0x3ff)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void upd7004_device::device_start()
{
// resolve callbacks
m_eoc_cb.resolve_safe();
m_eoc_ff_cb.resolve_safe();
m_in_cb.resolve_all_safe(0x3ff);
// allocate timers
m_cycle_timer = timer_alloc(FUNC(upd7004_device::update_state), this);
m_cycle_timer->adjust(attotime::never);
// register for save states
save_item(NAME(m_state));
save_item(NAME(m_div));
save_item(NAME(m_code));
save_item(NAME(m_address));
save_item(NAME(m_sar));
}
//-------------------------------------------------
// update_state -
//-------------------------------------------------
TIMER_CALLBACK_MEMBER(upd7004_device::update_state)
{
switch (m_state)
{
case STATE_IDLE:
m_cycle_timer->adjust(attotime::never);
break;
case STATE_CONVERSION_START:
m_sar = m_in_cb[m_address](0);
// the conversion takes 96 to 104 cycles
m_state = STATE_CONVERSION_DONE;
m_cycle_timer->adjust(attotime::from_ticks(100, clock() / m_div));
break;
case STATE_CONVERSION_DONE:
{
// set eoc
m_eoc_cb(1);
m_eoc_ff_cb(1);
m_state = STATE_IDLE;
m_cycle_timer->adjust(attotime::never);
LOG("Conversion finished, result: %03x\n", m_sar);
break;
}
}
}
//**************************************************************************
// INTERFACE
//**************************************************************************
uint8_t upd7004_device::read(offs_t offset)
{
uint8_t data = 0xff;
// connected to a flip-flop, cleared on read
m_eoc_ff_cb(0);
switch (offset)
{
case 0:
// low-byte data output
data = (m_sar & 0x03) << 6;
break;
case 1:
// high-byte data output
data = (m_sar >> 2) & 0xff;
break;
}
return data;
}
void upd7004_device::write(offs_t offset, uint8_t data)
{
switch (offset)
{
case 0:
// address set
m_address = data & 0x07;
// reset eoc
m_eoc_cb(0);
// start conversion timer
m_state = STATE_CONVERSION_START;
m_cycle_timer->adjust(attotime::from_hz(clock() / m_div));
LOG("Select address %d\n", m_address);
break;
case 1:
// initialize
m_div = 1 << (data & 0x03);
m_code = data & 0x04;
logerror("Initialize with clock division ratio %d, %s data\n", m_div, m_code ? "2s complement" : "binary");
if (m_code)
logerror("Warning: 2s complement data unimplemented\n");
break;
}
}
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