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la120: Write noninverted clock first; make ER1400 address decoding more efficient (nw)

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This commit is contained in:
AJR 2018-01-01 03:20:31 -05:00
parent 7c2220e8ca
commit 1ed7fe1518
2 changed files with 30 additions and 22 deletions
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15
src/devices/machine/er1400.cpp
View File

@ -115,10 +115,12 @@ void er1400_device::read_data()
int selected = 0;
m_data_register = 0;
for (int tens = 10; tens < 20; tens++)
{
if (BIT(m_address_register, tens))
{
for (int units = 0; units < 10; units++)
{
if (BIT(m_address_register, tens) && BIT(m_address_register, units))
if (BIT(m_address_register, units))
{
offs_t offset = 10 * (tens - 10) + units;
logerror("Reading data at %d (%04X) into register\n", offset, m_data_array[offset]);
@ -127,6 +129,7 @@ void er1400_device::read_data()
}
}
}
}
if (selected != 1)
logerror("%d addresses selected for read operation\n", selected);
@ -142,10 +145,12 @@ void er1400_device::write_data()
{
int selected = 0;
for (int tens = 10; tens < 20; tens++)
{
if (BIT(m_address_register, tens))
{
for (int units = 0; units < 10; units++)
{
if (BIT(m_address_register, tens) && BIT(m_address_register, units))
if (BIT(m_address_register, units))
{
offs_t offset = 10 * (tens - 10) + units;
if ((m_data_array[offset] & ~m_data_register) != 0)
@ -157,6 +162,7 @@ void er1400_device::write_data()
}
}
}
}
if (selected != 1)
logerror("%d addresses selected for write operation\n", selected);
@ -172,10 +178,12 @@ void er1400_device::erase_data()
{
int selected = 0;
for (int tens = 10; tens < 20; tens++)
{
if (BIT(m_address_register, tens))
{
for (int units = 0; units < 10; units++)
{
if (BIT(m_address_register, tens) && BIT(m_address_register, units))
if (BIT(m_address_register, units))
{
offs_t offset = 10 * (tens - 10) + units;
if (m_data_array[offset] != 0x3fff)
@ -187,6 +195,7 @@ void er1400_device::erase_data()
}
}
}
}
if (selected != 1)
logerror("%d addresses selected for erase operation\n", selected);

3
src/mame/drivers/decwritr.cpp
View File

@ -151,14 +151,13 @@ WRITE8_MEMBER( decwriter_state::la120_NVR_w )
m_maincpu->adjust_icount(-1);
// ER1400 has negative logic, but 7406 inverters are used
m_nvm->clock_w(BIT(offset, 0));
m_nvm->c3_w(BIT(offset, 10));
m_nvm->c2_w(BIT(offset, 9));
m_nvm->c1_w(BIT(offset, 8));
// C2 is used to disable pullup on data line
m_nvm->data_w(!BIT(offset, 9) ? 0 : !BIT(data, 7));
m_nvm->clock_w(!BIT(offset, 0));
}
/* todo: fully reverse engineer DC305 ASIC */