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// license:BSD-3-Clause
// copyright-holders:Patrick Mackinlay
/*
* An implementation of the Xilinx XC1700E family of serial configuration PROM
* devices, including:
*
* Part Capacity Variants
* -------- --------- ----------------
* XC1736E 36,288
* XC1765E 65,536 XC1765EL
* XC17128E 131,072 XC17128EL
* XC17256E 262,144 XC17256EL
* XC17512L 524,288
* XC1701 1,048,576 XC1701L, XQ1701L
* XC1702L 2,097,152
* XC1704L 4,194,304
*
* The input C̅E̅ and CLK lines have not been explicitly implemented; these are
* assumed to be asserted as expected before/during data read. The effect of
* C̅E̅O̅ can be obtained by connecting the cascade_r callback to the data_r of
* the cascaded device and resetting all devices when needed.
*
* This implementation assumes the input data is stored least-significant bit
* first; i.e. the first bit read out of the device is held in the LSB of the
* first byte of the memory region. This convention matches at least one
* dumping device tested.
*
* Sources:
*
* http://www.xilinx.com/support/documentation/data_sheets/ds027.pdf
*
*/
#include "emu.h"
#include "xc1700e.h"
#define VERBOSE 0
#include "logmacro.h"
DEFINE_DEVICE_TYPE(XC1736E, xc1736e_device, "xc1736e", "Xilinx 36,288 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC1765E, xc1765e_device, "xc1765e", "Xilinx 65,536 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC17128E, xc17128e_device, "xc17128e", "Xilinx 131,072 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC17256E, xc17256e_device, "xc17256e", "Xilinx 262,144 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC17512L, xc17512l_device, "xc17512l", "Xilinx 524,288 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC1701, xc1701_device, "xc1701", "Xilinx 1,048,576 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC1702L, xc1702l_device, "xc1702l", "Xilinx 2,097,152 bit Serial PROM")
DEFINE_DEVICE_TYPE(XC1704L, xc1704l_device, "xc1704l", "Xilinx 4,194,304 bit Serial PROM")
base_xc1700e_device::base_xc1700e_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, u32 capacity)
: device_t(mconfig, type, tag, owner, clock)
, m_capacity(capacity)
, m_region(*this, DEVICE_SELF)
, m_cascade_cb(*this, 1)
, m_reset(true)
, m_address(0)
{
}
void base_xc1700e_device::device_start()
{
save_item(NAME(m_reset));
save_item(NAME(m_address));
}
void base_xc1700e_device::reset_w(int state)
{
if (state)
m_address = 0;
m_reset = bool(state);
}
int base_xc1700e_device::data_r()
{
if (m_reset)
return 1;
if (m_address < m_capacity)
{
int const data = BIT(m_region->as_u8(m_address >> 3), m_address & 7);
m_address++;
return data;
}
else
return m_cascade_cb();
}
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