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isbc8030: Remove hacky and superfluous UI-configurable baud clock

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This commit is contained in:
AJR 2017-10-27 15:16:33 -04:00
parent db96395e5d
commit 25a2a8bd27
1 changed files with 2 additions and 55 deletions
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57
src/mame/drivers/isbc8030.cpp
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@ -35,7 +35,6 @@ X Examine and modify CPU registers
#include "machine/pit8253.h"
#include "machine/i8255.h"
#include "machine/i8251.h"
#include "machine/clock.h"
#include "bus/rs232/rs232.h"
#define I8259A_TAG "pic8259"
@ -56,15 +55,8 @@ public:
, m_pic(*this, I8259A_TAG)
, m_pit(*this, I8253_TAG)
, m_rs232(*this, RS232_TAG)
, m_usart_baud_rate(*this, I8251A_BAUD_TAG)
, m_usart_divide_counter(0)
, m_usart_clock_state(0)
{ }
DECLARE_WRITE_LINE_MEMBER( usart_clock_tick );
DECLARE_WRITE_LINE_MEMBER( isbc8030_tmr2_w );
private:
required_device<cpu_device> m_maincpu;
required_device<i8251_device> m_usart;
@ -72,10 +64,6 @@ private:
required_device<pic8259_device> m_pic;
required_device<pit8253_device> m_pit;
required_device<rs232_port_device> m_rs232;
required_ioport m_usart_baud_rate;
uint8_t m_usart_divide_counter;
uint8_t m_usart_clock_state;
};
static ADDRESS_MAP_START(isbc8030_mem, AS_PROGRAM, 8, isbc8030_state)
@ -95,46 +83,8 @@ static ADDRESS_MAP_START(isbc8030_io, AS_IO, 8, isbc8030_state)
ADDRESS_MAP_END
static INPUT_PORTS_START( isbc8030 )
PORT_START(I8251A_BAUD_TAG)
PORT_DIPNAME( 0x3f, 0x01, "i8251 Baud Rate" )
PORT_DIPSETTING( 0x01, "4800")
PORT_DIPSETTING( 0x02, "2400")
PORT_DIPSETTING( 0x04, "1200")
PORT_DIPSETTING( 0x08, "600")
PORT_DIPSETTING( 0x10, "300")
PORT_DIPSETTING( 0x20, "150")
PORT_DIPSETTING( 0x40, "75")
INPUT_PORTS_END
WRITE_LINE_MEMBER( isbc8030_state::usart_clock_tick )
{
uint8_t old_counter = m_usart_divide_counter;
m_usart_divide_counter++;
uint8_t transition = (old_counter ^ m_usart_divide_counter) & m_usart_baud_rate->read();
if (transition)
{
m_usart->write_txc(m_usart_clock_state);
m_usart->write_rxc(m_usart_clock_state);
m_usart_clock_state ^= 1;
}
}
WRITE_LINE_MEMBER( isbc8030_state::isbc8030_tmr2_w )
{
m_usart->write_rxc(state);
m_usart->write_txc(state);
}
static DEVICE_INPUT_DEFAULTS_START( terminal ) // set up terminal to default to 4800
DEVICE_INPUT_DEFAULTS( "RS232_RXBAUD", 0xff, RS232_BAUD_4800 )
DEVICE_INPUT_DEFAULTS( "RS232_TXBAUD", 0xff, RS232_BAUD_4800 )
DEVICE_INPUT_DEFAULTS( "RS232_STARTBITS", 0xff, RS232_STARTBITS_1 )
DEVICE_INPUT_DEFAULTS( "RS232_DATABITS", 0xff, RS232_DATABITS_8 )
DEVICE_INPUT_DEFAULTS( "RS232_PARITY", 0xff, RS232_PARITY_NONE )
DEVICE_INPUT_DEFAULTS( "RS232_STOPBITS", 0xff, RS232_STOPBITS_1 )
DEVICE_INPUT_DEFAULTS_END
static MACHINE_CONFIG_START( isbc8030 )
/* basic machine hardware */
MCFG_CPU_ADD("maincpu", I8085A, XTAL_22_1184MHz / 4)
@ -149,7 +99,8 @@ static MACHINE_CONFIG_START( isbc8030 )
MCFG_PIT8253_OUT0_HANDLER(DEVWRITELINE(I8259A_TAG, pic8259_device, ir0_w))
MCFG_PIT8253_CLK1(XTAL_22_1184MHz / 18)
MCFG_PIT8253_CLK2(XTAL_22_1184MHz / 18)
MCFG_PIT8253_OUT2_HANDLER(WRITELINE(isbc8030_state, isbc8030_tmr2_w))
MCFG_PIT8253_OUT2_HANDLER(DEVWRITELINE(I8251A_TAG, i8251_device, write_rxc))
MCFG_DEVCB_CHAIN_OUTPUT(DEVWRITELINE(I8251A_TAG, i8251_device, write_txc))
MCFG_DEVICE_ADD(I8251A_TAG, I8251, 0)
MCFG_I8251_TXD_HANDLER(DEVWRITELINE(RS232_TAG, rs232_port_device, write_txd))
@ -162,10 +113,6 @@ static MACHINE_CONFIG_START( isbc8030 )
MCFG_RS232_RXD_HANDLER(DEVWRITELINE(I8251A_TAG, i8251_device, write_rxd))
MCFG_RS232_DSR_HANDLER(DEVWRITELINE(I8251A_TAG, i8251_device, write_dsr))
MCFG_RS232_CTS_HANDLER(DEVWRITELINE(I8251A_TAG, i8251_device, write_cts))
MCFG_DEVICE_CARD_DEVICE_INPUT_DEFAULTS("terminal", terminal)
MCFG_DEVICE_ADD("usart_clock", CLOCK, XTAL_18_432MHz/60)
MCFG_CLOCK_SIGNAL_HANDLER(WRITELINE(isbc8030_state, usart_clock_tick))
MACHINE_CONFIG_END
/* ROM definition */