diff options
| author | 2025-08-29 10:32:19 +0200 | |
|---|---|---|
| committer | 2025-08-29 10:32:30 +0200 | |
| commit | 83f9fd1a1bca88741eb24e7ee9e4a65ac467f0be (patch) | |
| tree | 3a6e0db8b4caab5496d807cc2a9f79bb1ea99127 | |
| parent | c65b7dbae009b28487a834ba5b5d76024346f654 (diff) | |
sn76496: add btanb note
| -rw-r--r-- | src/devices/sound/sn76496.cpp | 12 | ||||
| -rw-r--r-- | src/mame/sanritsu/bankp.cpp | 5 |
2 files changed, 12 insertions, 5 deletions
diff --git a/src/devices/sound/sn76496.cpp b/src/devices/sound/sn76496.cpp index a9bd81fcff0..24c4d45c250 100644 --- a/src/devices/sound/sn76496.cpp +++ b/src/devices/sound/sn76496.cpp @@ -99,8 +99,10 @@ the others, as in real life. 15/02/2010: Lord Nightmare & Michael Zapf (additional testing by PlgDavid) - Fix noise period when set to mirror channel 3 and channel 3 period is set to 0 (tested on hardware for noise, wave needs tests) - MZ - Fix phase of noise on sn94624 and sn76489; all chips use a standard XOR, the only inversion is the output itself - LN, Plgdavid + Fix noise period when set to mirror channel 3 and channel 3 period is set to 0 + (tested on hardware for noise, wave needs tests) - MZ + Fix phase of noise on sn94624 and sn76489; all chips use a standard XOR, the only + inversion is the output itself - LN, Plgdavid Thanks to PlgDavid and Michael Zapf for providing samples which helped immensely here. 23/02/2011: Lord Nightmare & Enik @@ -138,6 +140,10 @@ other variants, the NCR-derived variants are implied to ignore writes to regs 1,3,5,6,7 if 0x80 is not set. This needs to be verified on real hardware. + BTANB: + * Unless the registers are quickly initialized by software, non-Sega chips + output a low-pitch beep at cold boot, eg. bbcm, bankp, exedexes, docastle. + ***************************************************************************/ #include "emu.h" @@ -239,8 +245,8 @@ void sn76496_base_device::device_start() for (int i = 0; i < 4; i++) { m_output[i] = 0; + m_count[i] = 0; m_period[i] = (m_sega_style_psg || i == 3) ? 0 : 0x400; - m_count[i] = (m_sega_style_psg || i == 3) ? 0 : 0x400; } m_RNG = m_feedback_mask; diff --git a/src/mame/sanritsu/bankp.cpp b/src/mame/sanritsu/bankp.cpp index 5498c9eac93..4bb45b21309 100644 --- a/src/mame/sanritsu/bankp.cpp +++ b/src/mame/sanritsu/bankp.cpp @@ -557,6 +557,7 @@ void bankp_state::bankp(machine_config &config) // sound hardware SPEAKER(config, "mono").front_center(); + // 1.0 is ok, sound does not overflow other than the boot-up beep SN76489A(config, "sn1", 15.46848_MHz_XTAL / 6).add_route(ALL_OUTPUTS, "mono", 1.0); SN76489A(config, "sn2", 15.46848_MHz_XTAL / 6).add_route(ALL_OUTPUTS, "mono", 1.0); SN76489A(config, "sn3", 15.46848_MHz_XTAL / 6).add_route(ALL_OUTPUTS, "mono", 1.0); @@ -595,7 +596,7 @@ ROM_START( bankp ) ROM_REGION( 0x025c, "user1", 0 ) ROM_LOAD( "315-5074.2c.bin", 0x0000, 0x025b, CRC(2e57bbba) SHA1(c3e45e8a972342779442e50872a2f5f2d61e9c0a) ) - ROM_LOAD( "315-5073.pal16l4", 0x0000, 0x0001, NO_DUMP ) // read protected + ROM_LOAD( "315-5073.pal16l4", 0x025b, 0x0001, NO_DUMP ) // read protected ROM_END ROM_START( bankpt ) @@ -653,7 +654,7 @@ ROM_START( combh ) ROM_REGION( 0x025c, "user1", 0 ) ROM_LOAD( "315-5074.2c.bin", 0x0000, 0x025b, CRC(2e57bbba) SHA1(c3e45e8a972342779442e50872a2f5f2d61e9c0a) ) - ROM_LOAD( "315-5073.pal16l4", 0x0000, 0x0001, NO_DUMP ) // read protected + ROM_LOAD( "315-5073.pal16l4", 0x025b, 0x0001, NO_DUMP ) // read protected ROM_END } // anonymous namespace |
