mirror of
https://github.com/holub/mame
synced 2025-04-23 00:39:36 +03:00
i8155: Substantial rewrite of timer emulation
- Modernize logging (nw) - Abandon "RIOT" name properly belonging to MOS 6532 (nw) - Provide separate device type for 8156 (nw) mice.cpp: Eliminate clock rate hack (nw)
This commit is contained in:
AJR
parent
85283a8056
commit
4885c64bbd
@ -1,8 +1,11 @@
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// license:BSD-3-Clause
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// copyright-holders:Curt Coder
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// copyright-holders:Curt Coder,AJR
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/**********************************************************************
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Intel 8155/8156 - 2048-Bit Static MOS RAM with I/O Ports and Timer emulation
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Intel 8155/8156 - 2048-Bit Static MOS RAM with I/O Ports and Timer
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The timer primarily functions as a square-wave generator, but can
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also be programmed for a single-cycle low pulse on terminal count.
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The only difference between 8155 and 8156 is that pin 8 (CE) is
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active low on the former device and active high on the latter.
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@ -17,7 +20,8 @@
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TODO:
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- strobed mode
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- ALT 3 and ALT 4 strobed port modes
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- optional NVRAM backup for CMOS versions
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*/
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@ -26,15 +30,18 @@
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// device type definitions
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DEFINE_DEVICE_TYPE(I8155, i8155_device, "i8155", "Intel 8155 RIOT")
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const device_type I8156 = I8155;
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DEFINE_DEVICE_TYPE(I8155, i8155_device, "i8155", "Intel 8155 RAM, I/O & Timer")
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DEFINE_DEVICE_TYPE(I8156, i8156_device, "i8156", "Intel 8156 RAM, I/O & Timer")
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//**************************************************************************
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// MACROS / CONSTANTS
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//**************************************************************************
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#define LOG 0
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#define LOG_PORT (1U << 0)
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#define LOG_TIMER (1U << 1)
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#define VERBOSE (LOG_PORT | LOG_TIMER)
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#include "logmacro.h"
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enum
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{
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@ -93,10 +100,8 @@ enum
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#define STATUS_TIMER 0x40
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#define TIMER_MODE_MASK 0xc0
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#define TIMER_MODE_LOW 0x00
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#define TIMER_MODE_SQUARE_WAVE 0x40
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#define TIMER_MODE_SINGLE_PULSE 0x80
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#define TIMER_MODE_AUTOMATIC_RELOAD 0xc0
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#define TIMER_MODE_AUTO_RELOAD 0x40
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#define TIMER_MODE_TC_PULSE 0x80
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@ -117,20 +122,70 @@ ADDRESS_MAP_END
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inline uint8_t i8155_device::get_timer_mode()
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{
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return (m_count_length >> 8) & TIMER_MODE_MASK;
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return (m_count_loaded >> 8) & TIMER_MODE_MASK;
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}
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inline void i8155_device::timer_output()
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inline void i8155_device::timer_output(int to)
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{
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m_out_to_cb(m_to);
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if (to == m_to)
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return;
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if (LOG) logerror("8155 Timer Output: %u\n", m_to);
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m_to = to;
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m_out_to_cb(to);
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LOGMASKED(LOG_TIMER, "Timer output: %u\n", to);
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}
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inline void i8155_device::pulse_timer_output()
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inline void i8155_device::timer_stop_count()
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{
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m_to = 0; timer_output();
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m_to = 1; timer_output();
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// stop counting
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m_timer->enable(0);
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// clear timer output
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timer_output(1);
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}
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inline void i8155_device::timer_reload_count()
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{
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// valid counts range from 2 to 3FFF
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if ((m_count_length & 0x3fff) < 2)
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{
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timer_stop_count();
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return;
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}
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m_count_loaded = m_count_length;
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// begin the odd half of the count, with one extra cycle if count is odd
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m_counter = (m_count_loaded & 0x3ffe) | 1;
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m_count_extra = BIT(m_count_loaded, 0);
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// set up our timer
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m_timer->adjust(attotime::zero, 0, clocks_to_attotime(1));
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timer_output(1);
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switch (get_timer_mode())
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{
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case 0:
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// puts out LOW during second half of count
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LOGMASKED(LOG_TIMER, "Timer loaded with %d (Mode: LOW)\n", m_count_loaded & 0x3fff);
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break;
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case TIMER_MODE_AUTO_RELOAD:
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// square wave, i.e. the period of the square wave equals the count length programmed with automatic reload at terminal count
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LOGMASKED(LOG_TIMER, "Timer loaded with %d (Mode: Square wave)\n", m_count_loaded & 0x3fff);
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break;
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case TIMER_MODE_TC_PULSE:
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// single pulse upon TC being reached
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LOGMASKED(LOG_TIMER, "Timer loaded with %d (Mode: Single pulse)\n", m_count_loaded & 0x3fff);
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break;
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case TIMER_MODE_TC_PULSE | TIMER_MODE_AUTO_RELOAD:
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// automatic reload, i.e. single pulse every time TC is reached
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LOGMASKED(LOG_TIMER, "Timer loaded with %d (Mode: Automatic reload)\n", m_count_loaded & 0x3fff);
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break;
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}
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}
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inline int i8155_device::get_port_mode(int port)
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@ -210,7 +265,12 @@ inline void i8155_device::write_port(int port, uint8_t data)
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//-------------------------------------------------
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i8155_device::i8155_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
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: device_t(mconfig, I8155, tag, owner, clock),
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: i8155_device(mconfig, I8155, tag, owner, clock)
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{
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}
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i8155_device::i8155_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock)
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: device_t(mconfig, type, tag, owner, clock),
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device_memory_interface(mconfig, *this),
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m_in_pa_cb(*this),
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m_in_pb_cb(*this),
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@ -221,11 +281,26 @@ i8155_device::i8155_device(const machine_config &mconfig, const char *tag, devic
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m_out_to_cb(*this),
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m_command(0),
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m_status(0),
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m_count_length(0),
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m_count_loaded(0),
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m_counter(0),
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m_count_extra(false),
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m_to(0),
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m_space_config("ram", ENDIANNESS_LITTLE, 8, 8, 0, nullptr, *ADDRESS_MAP_NAME(i8155))
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{
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}
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//-------------------------------------------------
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// i8156_device - constructor
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//-------------------------------------------------
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i8156_device::i8156_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
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: i8155_device(mconfig, I8156, tag, owner, clock)
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{
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}
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//-------------------------------------------------
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// device_start - device-specific startup
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//-------------------------------------------------
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@ -251,6 +326,8 @@ void i8155_device::device_start()
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save_item(NAME(m_status));
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save_item(NAME(m_output));
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save_item(NAME(m_count_length));
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save_item(NAME(m_count_loaded));
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save_item(NAME(m_count_extra));
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save_item(NAME(m_counter));
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save_item(NAME(m_to));
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}
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@ -273,12 +350,8 @@ void i8155_device::device_reset()
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// clear timer flag
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m_status &= ~STATUS_TIMER;
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// stop counting
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m_timer->enable(0);
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// clear timer output
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m_to = 1;
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timer_output();
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// stop timer
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timer_stop_count();
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}
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@ -288,60 +361,52 @@ void i8155_device::device_reset()
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void i8155_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
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{
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// count down
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m_counter--;
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if (get_timer_mode() == TIMER_MODE_LOW)
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if (m_count_extra)
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{
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// pulse on every count
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pulse_timer_output();
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m_count_extra = false;
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return;
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}
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if (m_counter == 0)
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// count down by twos
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m_counter -= 2;
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if (m_counter == 1)
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{
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if (LOG) logerror("8155 Timer Count Reached\n");
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LOGMASKED(LOG_TIMER, "Timer count half finished\n");
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switch (get_timer_mode())
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// reload the even half of the count
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m_counter = m_count_loaded & 0x3ffe;
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// square wave modes produce a low output in the second half of the counting period
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if ((get_timer_mode() & TIMER_MODE_TC_PULSE) == 0)
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timer_output(0);
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}
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else if (m_counter == 2)
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{
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if ((get_timer_mode() & TIMER_MODE_TC_PULSE) != 0)
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{
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case TIMER_MODE_LOW:
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case TIMER_MODE_SQUARE_WAVE:
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// toggle timer output
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m_to = !m_to;
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timer_output();
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break;
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case TIMER_MODE_SINGLE_PULSE:
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case TIMER_MODE_AUTOMATIC_RELOAD:
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// pulse upon TC being reached
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pulse_timer_output();
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break;
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// pulse low on TC being reached
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timer_output(0);
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}
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// set timer flag
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m_status |= STATUS_TIMER;
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}
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else if (m_counter == 0)
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{
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timer_output(1);
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if ((m_command & COMMAND_TM_MASK) == COMMAND_TM_START)
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{
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// load new timer counter
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m_counter = m_count_length & 0x3fff;
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if (LOG) logerror("8155 Timer New Start\n");
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}
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else if ((m_command & COMMAND_TM_MASK) == COMMAND_TM_STOP_AFTER_TC || get_timer_mode() == TIMER_MODE_SINGLE_PULSE)
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if ((get_timer_mode() & TIMER_MODE_AUTO_RELOAD) == 0 || (m_command & COMMAND_TM_MASK) == COMMAND_TM_STOP_AFTER_TC)
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{
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// stop timer
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m_timer->enable(0);
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if (LOG) logerror("8155 Timer Stopped\n");
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timer_stop_count();
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LOGMASKED(LOG_TIMER, "Timer stopped\n");
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}
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else
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{
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// automatically reload the counter
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m_counter = m_count_length & 0x3fff;
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timer_reload_count();
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}
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// clear timer command
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m_command &= ~COMMAND_TM_MASK;
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}
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}
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@ -412,28 +477,28 @@ void i8155_device::register_w(int offset, uint8_t data)
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case REGISTER_COMMAND:
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m_command = data;
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if (LOG) logerror("8155 Port A Mode: %s\n", (data & COMMAND_PA) ? "output" : "input");
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if (LOG) logerror("8155 Port B Mode: %s\n", (data & COMMAND_PB) ? "output" : "input");
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LOGMASKED(LOG_PORT, "Port A Mode: %s\n", (data & COMMAND_PA) ? "output" : "input");
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LOGMASKED(LOG_PORT, "Port B Mode: %s\n", (data & COMMAND_PB) ? "output" : "input");
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if (LOG) logerror("8155 Port A Interrupt: %s\n", (data & COMMAND_IEA) ? "enabled" : "disabled");
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if (LOG) logerror("8155 Port B Interrupt: %s\n", (data & COMMAND_IEB) ? "enabled" : "disabled");
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LOGMASKED(LOG_PORT, "Port A Interrupt: %s\n", (data & COMMAND_IEA) ? "enabled" : "disabled");
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LOGMASKED(LOG_PORT, "Port B Interrupt: %s\n", (data & COMMAND_IEB) ? "enabled" : "disabled");
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switch (data & COMMAND_PC_MASK)
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{
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case COMMAND_PC_ALT_1:
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if (LOG) logerror("8155 Port C Mode: Alt 1\n");
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LOGMASKED(LOG_PORT, "Port C Mode: Alt 1\n");
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break;
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case COMMAND_PC_ALT_2:
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if (LOG) logerror("8155 Port C Mode: Alt 2\n");
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LOGMASKED(LOG_PORT, "Port C Mode: Alt 2\n");
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break;
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case COMMAND_PC_ALT_3:
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if (LOG) logerror("8155 Port C Mode: Alt 3\n");
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LOGMASKED(LOG_PORT, "Port C Mode: Alt 3\n");
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break;
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case COMMAND_PC_ALT_4:
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if (LOG) logerror("8155 Port C Mode: Alt 4\n");
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LOGMASKED(LOG_PORT, "Port C Mode: Alt 4\n");
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break;
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}
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@ -445,19 +510,17 @@ void i8155_device::register_w(int offset, uint8_t data)
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case COMMAND_TM_STOP:
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// NOP if timer has not started, stop counting if the timer is running
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if (LOG) logerror("8155 Timer Command: Stop\n");
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m_to = 1;
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timer_output();
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m_timer->enable(0);
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LOGMASKED(LOG_PORT, "Timer Command: Stop\n");
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timer_stop_count();
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break;
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case COMMAND_TM_STOP_AFTER_TC:
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// stop immediately after present TC is reached (NOP if timer has not started)
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if (LOG) logerror("8155 Timer Command: Stop after TC\n");
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LOGMASKED(LOG_PORT, "Timer Command: Stop after TC\n");
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break;
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case COMMAND_TM_START:
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if (LOG) logerror("8155 Timer Command: Start\n");
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LOGMASKED(LOG_PORT, "Timer Command: Start\n");
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if (m_timer->enabled())
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{
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@ -466,12 +529,7 @@ void i8155_device::register_w(int offset, uint8_t data)
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else
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{
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// load mode and CNT length and start immediately after loading (if timer is not running)
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m_counter = m_count_length & 0x3fff;
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if (clock() > 0) // a clock of 0 causes MAME to freeze.
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m_timer->adjust(attotime::zero, 0, attotime::from_hz(clock()));
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// clear timer command so this won't execute twice
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m_command &= ~COMMAND_TM_MASK;
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timer_reload_count();
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}
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break;
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}
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@ -491,35 +549,10 @@ void i8155_device::register_w(int offset, uint8_t data)
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case REGISTER_TIMER_LOW:
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m_count_length = (m_count_length & 0xff00) | data;
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if (LOG) logerror("8155 Count Length Low: %04x\n", m_count_length);
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break;
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case REGISTER_TIMER_HIGH:
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m_count_length = (data << 8) | (m_count_length & 0xff);
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if (LOG) logerror("8155 Count Length High: %04x\n", m_count_length);
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switch (data & TIMER_MODE_MASK)
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{
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case TIMER_MODE_LOW:
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// puts out LOW during second half of count
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if (LOG) logerror("8155 Timer Mode: LOW\n");
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break;
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case TIMER_MODE_SQUARE_WAVE:
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// square wave, i.e. the period of the square wave equals the count length programmed with automatic reload at terminal count
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if (LOG) logerror("8155 Timer Mode: Square wave\n");
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break;
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case TIMER_MODE_SINGLE_PULSE:
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// single pulse upon TC being reached
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if (LOG) logerror("8155 Timer Mode: Single pulse\n");
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break;
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case TIMER_MODE_AUTOMATIC_RELOAD:
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// automatic reload, i.e. single pulse every time TC is reached
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if (LOG) logerror("8155 Timer Mode: Automatic reload\n");
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break;
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}
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break;
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}
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}
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@ -2,8 +2,7 @@
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// copyright-holders:Curt Coder
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/**********************************************************************
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Intel 8155/8156 - 2048-Bit Static MOS RAM with I/O Ports and Timer emulation
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8156 is the same as 8155, except that chip enable is active high instead of low
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Intel 8155/8156 - 2048-Bit Static MOS RAM with I/O Ports and Timer
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**********************************************************************
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_____ _____
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@ -95,6 +94,8 @@ public:
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DECLARE_WRITE8_MEMBER( write );
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protected:
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i8155_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock);
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// device-level overrides
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virtual void device_start() override;
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virtual void device_reset() override;
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@ -103,8 +104,9 @@ protected:
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virtual space_config_vector memory_space_config() const override;
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inline uint8_t get_timer_mode();
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inline void timer_output();
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inline void pulse_timer_output();
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inline void timer_output(int to);
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inline void timer_stop_count();
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inline void timer_reload_count();
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inline int get_port_mode(int port);
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inline uint8_t read_port(int port);
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inline void write_port(int port, uint8_t data);
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@ -125,16 +127,18 @@ private:
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// CPU interface
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int m_io_m; // I/O or memory select
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uint8_t m_ad; // address
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uint8_t m_ad; // address
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// registers
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uint8_t m_command; // command register
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uint8_t m_status; // status register
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uint8_t m_output[3]; // output latches
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uint8_t m_command; // command register
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uint8_t m_status; // status register
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uint8_t m_output[3]; // output latches
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// counter
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uint16_t m_count_length; // count length register
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uint16_t m_counter; // counter register
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uint16_t m_count_length; // count length register (assigned)
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uint16_t m_count_loaded; // count length register (loaded)
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uint16_t m_counter; // counter register
|
||||
bool m_count_extra; // extra cycle when count is odd
|
||||
int m_to; // timer output
|
||||
|
||||
// timers
|
||||
@ -144,9 +148,16 @@ private:
|
||||
};
|
||||
|
||||
|
||||
class i8156_device : public i8155_device
|
||||
{
|
||||
public:
|
||||
// construction/destruction
|
||||
i8156_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
|
||||
};
|
||||
|
||||
// device type definition
|
||||
DECLARE_DEVICE_TYPE(I8155, i8155_device)
|
||||
extern const device_type I8156;
|
||||
DECLARE_DEVICE_TYPE(I8156, i8156_device)
|
||||
|
||||
|
||||
#endif
|
||||
|
||||
@ -109,7 +109,7 @@ static MACHINE_CONFIG_START( mice )
|
||||
MCFG_RS232_CTS_HANDLER(DEVWRITELINE("uart", i8251_device, write_cts))
|
||||
MCFG_DEVICE_CARD_DEVICE_INPUT_DEFAULTS("terminal", terminal)
|
||||
|
||||
MCFG_DEVICE_ADD("rpt", I8155, XTAL_6_144MHz) // divider is likely to be 2; timer emulation appears faulty
|
||||
MCFG_DEVICE_ADD("rpt", I8155, XTAL_6_144MHz / 2)
|
||||
MCFG_I8155_IN_PORTC_CB(IOPORT("BAUD"))
|
||||
MCFG_I8155_OUT_TIMEROUT_CB(DEVWRITELINE("uart", i8251_device, write_txc))
|
||||
MCFG_DEVCB_CHAIN_OUTPUT(DEVWRITELINE("uart", i8251_device, write_rxc))
|
||||
|
||||
Loading…
Reference in New Issue
Block a user