ssystem3: remove obsolete workaround

This commit is contained in:
hap 2023-03-09 20:54:29 +01:00
parent 506e00ab88
commit dc8c36f996

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@ -43,11 +43,6 @@ reversi program called "The Moor". The chesscomputer was discontinued soon after
release, and none of the accessories or other games came out.
TODO:
- 6522 ACR register is initialized with 0xe3. Meaning: PA and PB inputs are set
to latch mode, but the program then never clocks the latch, it functions as if
it meant to write 0xe0. Maybe 6522 CA1 pin emulation is wrong? Documentation
says it's edge-triggered, but here it's tied to VCC. I added a trivial hack to
work around this, see rom defs.
- 2nd 7474 /2 clock divider on each 4000-7fff access, this also applies to 6522 clock
(doesn't affect chess calculation speed, only I/O access, eg. beeper pitch).
Should be doable to add, but 6522 device doesn't support live clock changes.
@ -540,9 +535,6 @@ ROM_START( ssystem3 )
ROM_LOAD("c19081e_ss-3-lrom.u4", 0x8000, 0x1000, CRC(9ea46ed3) SHA1(34eef85b356efbea6ddac1d1705b104fc8e2731a) ) // 2332
ROM_LOAD("c19082_ss-3-hrom.u5", 0x9000, 0x1000, CRC(52741e0b) SHA1(2a7b950f9810c5a14a1b9d5e6b2bd93da621662e) ) // "
// HACK! 6522 ACR register setup
ROM_FILL(0x946d, 1, 0xe0) // was 0xe3
ROM_REGION(0x10000, "subcpu", 0)
ROM_LOAD("c28a97m_ss-3l-rom", 0x4000, 0x0800, CRC(bf0b2a84) SHA1(286f56aca2e50b78ac1fae4a89413659aceb71d9) ) // 2316
@ -562,9 +554,6 @@ ROM_START( ssystem4 )
ROM_LOAD("c45022_ss4-mrom", 0xe000, 0x1000, CRC(c6110af1) SHA1(4b63454a23b2fe6b5c8f3fa6718eb49770cb6907) ) // "
ROM_LOAD("c45023_ss4-hrom", 0xf000, 0x1000, CRC(ab4a4343) SHA1(6eeee7168e13dc1115cb5833f1938a8ea8c01d69) ) // "
// HACK! 6522 ACR register setup
ROM_FILL(0xd05b, 1, 0xe0) // was 0xe3
ROM_REGION(53552, "screen", 0) // looks same, but different pinout
ROM_LOAD("ssystem4.svg", 0, 53552, CRC(b69b12e3) SHA1(c2e39d015397d403309f1c23619fe8abc3745d87) )
ROM_END