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starrider: few more notes (nw)

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This commit is contained in:
Vas Crabb 2019-05-26 15:43:33 +10:00
parent 626b566fee
commit 987365c5c5
1 changed files with 10 additions and 2 deletions
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12
src/mame/drivers/starrider.cpp
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@ -138,6 +138,9 @@
Q ______------------____________------------____________------------______ Q ______------------____________------------____________------------______
LATCH ______________--------________________--------________________--------__ LATCH ______________--------________________--------________________--------__
__----__----__----__----__----__----__----__----__----__----__----__---- __----__----__----__----__----__----__----__----__----__----__----__----
/SRL --------____--------------------____--------------------____------------
4MHz ___---___---___---___---___---___---___---___---___---___---___---___---
2MHz ______------______------______------______------______------______------
Video RAM consists of 6 4416 16k*4 DRAMs at U25, U26, U41, U42, U55 and Video RAM consists of 6 4416 16k*4 DRAMs at U25, U26, U41, U42, U55 and
U56. The CPU and DMA chips have their addressing mangled by the 6349 U56. The CPU and DMA chips have their addressing mangled by the 6349
@ -170,10 +173,13 @@
U14.6 (active low) 1111x xxxx xxxxxxxx xxxxxxxx U14.6 (active low) 1111x xxxx xxxxxxxx xxxxxxxx
U15.13 (active high) xxxxx xx11 xxxxxxxx xxxxxxxx (W)
U18.8 (active low) xxxxx xx10 xxxxxxxx xxxxxxxx (CPU access) U18.8 (active low) xxxxx xx10 xxxxxxxx xxxxxxxx (CPU access)
U46.3 /1E 11110 xxxx xxxxxxxx xxxxxxxx U46.3 /1E 11110 xxxx xxxxxxxx xxxxxxxx
U46.8 /1F 11111 xxxx xxxxxxxx xxxxxxxx U46.8 /1F 11111 xxxx xxxxxxxx xxxxxxxx
U46.11 (active low) 11110 xx01 xxxxxxxx xxxxxxxx
U33.8 (active low) 11001011 xxxxxxxx 0xcb00-0xcbff U33.8 (active low) 11001011 xxxxxxxx 0xcb00-0xcbff
@ -613,6 +619,8 @@ u16 sr_state::vgg_drams_map(u16 a) const
void sr_state::vgg_drams_w(offs_t offset, u8 data) void sr_state::vgg_drams_w(offs_t offset, u8 data)
{ {
if (((m_main_page & 0x03) == 0x03) || (((m_main_page & 0x03) == 0x01) && ((m_vgg_image_page & 0x1f) == 0x1e)))
offset ^= 0x8000;
u16 const addr(vgg_drams_map(offset)); u16 const addr(vgg_drams_map(offset));
if ((offset & 0xc000) != 0xc000) if ((offset & 0xc000) != 0xc000)
m_vgg_drams[addr] = data; m_vgg_drams[addr] = data;
@ -621,7 +629,7 @@ void sr_state::vgg_drams_w(offs_t offset, u8 data)
void sr_state::vgg_impg_w(u8 data) void sr_state::vgg_impg_w(u8 data)
{ {
// 6 bits latched by U13 (74LS173) but only 5 bits used // 6 bits latched by U13 (74LS173) but only 5 bits used
m_vgg_image_page = data & 0x1f; m_vgg_image_page = data & 0x3f;
} }
void sr_state::vgg_xlate_w(u8 data) void sr_state::vgg_xlate_w(u8 data)
@ -640,7 +648,7 @@ void sr_state::vgg_disable_w(u8 data)
void sr_state::vgg_color_palet_w(u8 data) void sr_state::vgg_color_palet_w(u8 data)
{ {
// all 8 bits latched by U94 (74LS374) but only 6 bits used // all 8 bits latched by U94 (74LS374) but only 6 bits used
m_vgg_color_palet = data & 0x3f; m_vgg_color_palet = data;
} }