Better MockingBoard detection

src/libsrc/apple/sndseq.pla

@@ -213,6 +213,36 @@ asm psgWrite(pVIA, reg, val)#0
         INX
         RTS
 end
+asm viaCheck(pVIA)#2
+        PHP
+        SEI
+        LDA     ESTKL,X
+        STA     TMPL
+        LDA     ESTKH,X
+        STA     TMPH
+        STX     ESP
+        LDX     #$80
+        LDY     #$04
+-       LDA     (TMP),Y
+        BMI     +
+        DEX
+        BNE     -
+        TXA                 ; TIMEOUT
+        BEQ     ++
++       TAX
+        LDA     (TMP),Y
+++      TAY
+        TXA
+        LDX     ESP
+        DEX
+        STA     ESTKL,X
+        STY     ESTKL+1,X
+        LDA     #$00
+        STA     ESTKH,X
+        STA     ESTKH+1,X
+        PLP
+        RTS
+end
 //
 // Apple II speaker tone generator routines
 //
@@ -374,14 +404,21 @@ end
 // Search slots for MockingBoard
 //
 def mbTicklePSG(pVIA)
-    pVIA->IER  = $7F  // Mask all interrupts
-    pVIA->ACR  = $00  // Stop T1 countdown
-    pVIA->DDRB = $FF  // Output enable port A and B
-    pVIA->DDRA = $FF
-    pVIA->IORA = $00 // Reset MockingBoard
-    if pVIA->IORA == $00
+    byte tmrBegin, tmrEnd
+    word tmrDiff
+    
+    tmrBegin, tmrEnd = viaCheck(pVIA)
+    tmrDiff = tmrEnd - tmrBegin
+    //puts("VIA address: $"); puth(pVIA); puts(" Timer Diff = "); puti(tmrDiff); putln
+    if tmrDiff == 10
+        pVIA->IER  = $7F  // Mask all interrupts
+        //pVIA->ACR  = $00  // Stop T1 countdown
+        pVIA->DDRB = $FF  // Output enable port A and B
+        pVIA->DDRA = $FF
+        pVIA->IORA = $00 // Reset MockingBoard
+        //if pVIA->IORA == $00
         pVIA->IORA = $04 // Inactive MockingBoard control lines
-        if pVIA->IORA == $04
+        //if pVIA->IORA == $04
             //
             // At least we know we have some sort of R/W in the ROM
             // address space. Most likely a MockingBoard or John Bell
@@ -392,7 +429,7 @@ def mbTicklePSG(pVIA)
             //if mbReadP(pVIA, 2) == $7E and mbReadP(pVIA, 3) == $0A
                 return pVIA
             //fin
-        fin
+        //fin
     fin
     return 0
 end
@@ -632,7 +669,7 @@ def mbSequence(yield, func)#0
         psgWrite(mbVIA2, BENVAMP, $00)
         psgWrite(mbVIA2, CENVAMP, $00)
     fin
-    mbVIA1->ACR = $00 // Stop T1 countdown
+    //mbVIA1->ACR = $00 // Stop T1 countdown
     mbVIA1->IER = $7F // Mask all interrupts
     mbVIA1->IFR = $40 // Clear interrupt
     setStatusReg(status)
@@ -821,14 +858,15 @@ when MACHID & MACHID_MODEL
         return -1
         break
     otherwise
-        puts("MockingBoard Slot:\n")
-        puts("ENTER = None\n")
-        puts("0     = Scan\n")
-        puts("1-7   = Slot #\n")
-        instr = gets('>'|$80)
-        if ^instr
-            mbSlot = mbSearch(^(instr + 1) - '0')
-        fin
+        //puts("MockingBoard Slot:\n")
+        //puts("ENTER = None\n")
+        //puts("0     = Scan\n")
+        //puts("1-7   = Slot #\n")
+        //instr = gets('>'|$80)
+        //if ^instr
+        //    mbSlot = mbSearch(^(instr + 1) - '0')
+        //fin
+        mbSlot = mbSearch(0)
         break
 wend
 if mbSlot < 0