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Fix Echo+ to have same chip-select polarity and bits as Phasor

This commit is contained in:
tomcw 2024-01-30 21:23:59 +00:00
parent 53fddfe41a
commit def144a684
1 changed files with 5 additions and 7 deletions
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12
source/Mockingboard.cpp
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@ -226,12 +226,9 @@ void MockingboardCard::WriteToORB(BYTE subunit, BYTE subunitForAY/*=0*/)
#else
if (m_phasorEnable)
{
const int kAY1 = 2; // Phasor mode: bit4=0 (active low) selects the 1st AY8913, ie. the only AY8913 in Mockingboard mode (confirmed on real Phasor h/w)
// Echo+ mode: bit3=1 (active high) selects the 1st AY8913
const int kAY2 = 1; // Phasor mode: bit3=0 (active low) selects the 2nd AY8913 attached to this 6522 (unavailable in Mockingboard mode)
// Echo+ mode: bit4=1 (active high) selects the 2nd AY8913
const int nAY_CS = (m_phasorMode == PH_EchoPlus) ? ((value >> 4) & 1) | ((value >> 2) & 2) // swap bits 4 & 3
: (m_phasorMode == PH_Phasor) ? (~(value >> 3) & 3)
const int kAY1 = 2; // Phasor/Echo+ mode: bit4=0 (active low) selects the 1st AY8913, ie. the only AY8913 in Mockingboard mode (confirmed on real Phasor h/w)
const int kAY2 = 1; // Phasor/Echo+ mode: bit3=0 (active low) selects the 2nd AY8913 attached to this 6522 (unavailable in Mockingboard mode)
const int nAY_CS = (m_phasorMode == PH_Phasor || m_phasorMode == PH_EchoPlus) ? (~(value >> 3) & 3)
: kAY1; // Anything else is Mockingboard
if (m_phasorMode == PH_EchoPlus)
@ -306,7 +303,8 @@ void MockingboardCard::AY8913_Write(BYTE subunit, BYTE ay, BYTE value)
if (!m_phasorEnable || m_phasorMode == PH_Mockingboard)
_ASSERT(ay == AY8913_DEVICE_A);
if (nAYFunc == AY_READ || nAYFunc == AY_WRITE || nAYFunc == AY_LATCH)
_ASSERT(state == AY_INACTIVE);
if ((nAYFunc != state) || (m_phasorEnable && m_phasorMode != PH_EchoPlus)) // Deater's Xmas2023 demo interleaves writes to both AY's (need this line to avoid ASSERT for Echo+)
_ASSERT(state == AY_INACTIVE);
#endif
if (state == AY_INACTIVE) // GH#320: functions only work from inactive state