Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-07-10 20:24:49 +03:00
Code Issues Actions 4 Packages Projects Releases Wiki Activity

am9517a: Assert EOP during rather than after final DMA transfer

Browse Source 
uPD765 may not care much about the timing of this signal, but other devices (notably NCR5380) expect it to occur simultaneously with the read/write strobe.

This *might* break drivers/devices that expect EOP to be continuously active as it was previously emulated, rather than pulsed. Those likely need to latch the edge of EOP or one of the ACK signals.
This commit is contained in:
AJR 2020-04-13 22:54:54 -04:00
parent 86e7693df0
commit a93fbd3c9c
1 changed files with 24 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
src/devices/machine/am9517a.cpp
View File

@ -397,8 +397,7 @@ void am9517a_device::end_of_process()
m_mask |= 1 << m_current_channel;
}
// signal end of process
set_eop(ASSERT_LINE);
set_eop(CLEAR_LINE);
set_hreq(0);
m_current_channel = -1;
@ -506,6 +505,8 @@ void am9517a_device::device_start()
m_address_mask = 0xffff;
// force clear upon initial reset
m_eop = ASSERT_LINE;
}
@ -525,10 +526,9 @@ void am9517a_device::device_reset()
m_current_channel = -1;
m_last_channel = 3;
m_hreq = -1;
m_eop = 0;
set_hreq(0);
set_eop(ASSERT_LINE);
set_eop(CLEAR_LINE);
set_dack();
}
@ -545,8 +545,6 @@ void am9517a_device::execute_run()
switch (m_state)
{
case STATE_SI:
set_eop(CLEAR_LINE);
if (!COMMAND_DISABLE)
{
int priority[] = { 0, 1, 2, 3 };
@ -622,10 +620,23 @@ void am9517a_device::execute_run()
case STATE_S2:
set_dack();
m_state = COMMAND_COMPRESSED_TIMING ? STATE_S4 : STATE_S3;
if (COMMAND_COMPRESSED_TIMING)
{
// signal end of process during last cycle
if (m_channel[m_current_channel].m_count == 0)
set_eop(ASSERT_LINE);
m_state = STATE_S4;
}
else
m_state = STATE_S3;
break;
case STATE_S3:
// signal end of process during last cycle
if (m_channel[m_current_channel].m_count == 0)
set_eop(ASSERT_LINE);
dma_read();
if (COMMAND_EXTENDED_WRITE)
@ -685,6 +696,10 @@ void am9517a_device::execute_run()
break;
case STATE_S23:
// signal end of process during last cycle
if (m_channel[m_current_channel].m_count == 0)
set_eop(ASSERT_LINE);
m_state = STATE_S24;
break;
@ -1260,10 +1275,9 @@ void pcxport_dmac_device::device_reset()
m_current_channel = -1;
m_last_channel = 3;
m_hreq = -1;
m_eop = 0;
set_hreq(0);
set_eop(ASSERT_LINE);
set_eop(CLEAR_LINE);
set_dack();
}
@ -1292,8 +1306,7 @@ void pcxport_dmac_device::end_of_process()
}
// don't mask out channel if not autoinitialize
// signal end of process
set_eop(ASSERT_LINE);
set_eop(CLEAR_LINE);
set_hreq(0);
m_current_channel = -1;