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Stop the internal timer if DTR is high and there is no character being received as neither the transmit or receive will do anything anyway. The default is for the internal divider to be disabled so if the chip wasn't initialised then the timer would be running at the full rate of the xtal. (nw)

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smf- 2014-04-11 08:54:54 +00:00
parent 82a53e9745
commit fbc648ce50
1 changed files with 16 additions and 1 deletions
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17
src/emu/machine/mos6551.c
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@ -240,7 +240,15 @@ void mos6551_device::update_divider()
m_tx_internal_clock = true;
m_divide = 16;
scale = (double) 1 / scale;
if (!m_dtr || m_rx_state != STATE_START)
{
scale = (double) 1 / scale;
}
else
{
scale = 0;
}
}
else
{
@ -355,6 +363,8 @@ void mos6551_device::write_command(UINT8 data)
m_tx_output = OUTPUT_MARK;
output_txd(1);
}
update_divider();
}
READ8_MEMBER( mos6551_device::read )
@ -629,6 +639,11 @@ WRITE_LINE_MEMBER(mos6551_device::receiver_clock)
}
m_rx_state = STATE_START;
if (m_dtr)
{
update_divider();
}
}
break;
}