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nec/pc8401a.cpp: rework irq to be a free running timer

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This commit is contained in:
angelosa 2023-12-19 04:15:22 +01:00
parent 835415a58c
commit 61ab1c2530
1 changed files with 23 additions and 30 deletions
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53
src/mame/nec/pc8401a.cpp
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@ -7,25 +7,27 @@
TODO:
- Need a media device to be in any way useful
(throws E27 directory full if attempting to create a new file thru WS -> D -> new file name)
- keyboard interrupt
- keyboard key modifiers (f6-f10 presumably needs holding shift like PC-8001);
\- Option testing beyond f5;
\- Cannot do anything useful with filer (usage: "filer <filename>"), needs F6;
- RTC TP pulse
- clock does not advance in menu (timer irq?)
- some unclear bits in the banking scheme;
- mirror e800-ffff to 6800-7fff (why? -AS)
- How PC-8508A really banks?
- soft power on/off
- idle sleep timer off by a bunch of seconds (option -> power to test);
- NVRAM
- 8251 USART
- 8255 ports
- Merge keyboard with pc8001 / pc8801 / pc88va (same keys, running on a MCU like VA)
- PC-8431A FDC is same family as PC-80S31K, basically the 3.5" version of it.
Likely none of the available BIOSes fits here.
Notes:
- Need to format internal RAM before using WS, "format -> F1 -> y"
- peripherals
* PC-8431A Dual Floppy Drive
* PC-8441A CRT / Disk Interface (MC6845, monochrome)
* PC-8441A CRT / Disk Interface (MC6845, monochrome & color variants)
* PC-8461A 1200 Baud Modem
* PC-8407A 128KB RAM Expansion
* PC-8508A ROM/RAM Cartridge
@ -138,7 +140,7 @@ private:
void bankdev0_map(address_map &map);
// TODO: these two should really be inside ram_device instead
// TODO: temp, should really be a NVRAM device
template <unsigned StartBase> uint8_t ram_r(address_space &space, offs_t offset)
{
const offs_t memory_offset = StartBase + offset;
@ -180,33 +182,27 @@ void pc8401a_state::pc8500_lcdc(address_map &map)
void pc8401a_state::scan_keyboard()
{
if (!m_key_irq_enable)
return;
int strobe = 0;
/* scan keyboard */
// TODO: is this just a generic key pressed shortcut rather than being MCU based?
for (int row = 0; row < 10; row++)
{
uint8_t data = m_io_y[row]->read();
if (data != 0xff)
{
strobe = 1;
m_key_latch = data;
//strobe = 1;
m_key_latch |= 1;
}
}
if (!m_key_strobe && strobe)
{
m_maincpu->set_input_line_and_vector(INPUT_LINE_IRQ0, ASSERT_LINE, 0xef); // Z80 - RST 28h
}
if (strobe) m_key_strobe = strobe;
m_maincpu->set_input_line_and_vector(INPUT_LINE_IRQ0, ASSERT_LINE, 0xef); // Z80 - RST 28h
m_key_strobe = 1;
}
TIMER_DEVICE_CALLBACK_MEMBER(pc8401a_state::keyboard_tick)
{
scan_keyboard();
if (m_key_irq_enable)
scan_keyboard();
}
/*
@ -215,8 +211,8 @@ TIMER_DEVICE_CALLBACK_MEMBER(pc8401a_state::keyboard_tick)
* 0 key pressed
* 1
* 2
* 3
* 4 must be 1 or CPU goes to HALT (power switch status?)
* 3 <unknown>, disables all keys if on
* 4 must be 1 or CPU goes to HALT (power status)
* 5
* 6
* 7
@ -405,14 +401,14 @@ void pc8401a_state::pc8500_io(address_map &map)
// map(0x80, 0x80) modem status, set to 0xff to boot
// map(0x8b, 0x8b)
// map(0x90, 0x93)
// map(0x98, 0x98).w(m_crtc, FUNC(mc6845_device::address_w));
// map(0x99, 0x99).rw(m_crtc, FUNC(mc6845_device::register_r), FUNC(mc6845_device::register_w));
// map(0x98, 0x98).w(m_crtc, FUNC(mc6845_device::address_w));
// map(0x99, 0x99).rw(m_crtc, FUNC(mc6845_device::register_r), FUNC(mc6845_device::register_w));
map(0x98, 0x99).noprw();
// map(0xa0, 0xa1)
map(0xb0, 0xb3).w(FUNC(pc8401a_state::io_rom_addr_w));
map(0xb3, 0xb3).r(FUNC(pc8401a_state::io_rom_data_r));
// map(0xc8, 0xc8)
// map(0xfc, 0xff).rw(I8255A_TAG, FUNC(i8255_device::read), FUNC(i8255_device::write));
// map(0xfc, 0xff).rw(I8255A_TAG, FUNC(i8255_device::read), FUNC(i8255_device::write));
map(0xfc, 0xff).noprw();
}
@ -548,7 +544,8 @@ void pc8401a_state::pc8500(machine_config &config)
m_maincpu->set_addrmap(AS_PROGRAM, &pc8401a_state::pc8401a_mem);
m_maincpu->set_addrmap(AS_IO, &pc8401a_state::pc8500_io);
TIMER(config, "keyboard").configure_periodic(FUNC(pc8401a_state::keyboard_tick), attotime::from_hz(44));
// unknown frequency, roughly fits idle sleep mode
TIMER(config, "keyboard").configure_periodic(FUNC(pc8401a_state::keyboard_tick), attotime::from_hz(60));
UPD1990A(config, m_rtc);
@ -590,10 +587,6 @@ ROM_START( pc8500 )
ROM_REGION( 0x20000, IPL_TAG, ROMREGION_ERASEFF )
ROM_LOAD( "pc8500.bin", 0x0000, 0x10000, CRC(c2749ef0) SHA1(f766afce9fda9ec84ed5b39ebec334806798afb3) )
// TODO: identify this
ROM_REGION( 0x1000, "mcu", 0)
ROM_LOAD( "kbd.rom", 0x0000, 0x1000, NO_DUMP )
//ROM_REGION( 0x1000, "chargen", 0 )
//ROM_LOAD( "pc8441a.bin", 0x0000, 0x1000, NO_DUMP )
ROM_END