From eecc39834949e6affbf3268cb5405a296cd12216 Mon Sep 17 00:00:00 2001
From: Javier Degirolmo
Date: Mon, 22 Apr 2013 05:30:00 -0300
Subject: Now you can change the sample rate of PCM instruments

---
 src-68k/echo.68k | 53 +++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 49 insertions(+), 4 deletions(-)

(limited to 'src-68k/echo.68k')

diff --git a/src-68k/echo.68k b/src-68k/echo.68k
index 9b1341f..94e42ca 100644
--- a/src-68k/echo.68k
+++ b/src-68k/echo.68k
@@ -61,13 +61,14 @@ Echo_SendCommand:
     rts                             ; End of subroutine
 
 ;****************************************************************************
-; Echo_SendCommandEx
+; Echo_SendCommandAddr
 ; Sends an Echo command (with address parameter)
 ;
 ; input d0.b ... Echo command
 ; input a0.l ... Address parameter
 ;****************************************************************************
 
+Echo_SendCommandAddr:
 Echo_SendCommandEx:
     movem.l d0-d1, -(sp)            ; Save register
 
@@ -105,6 +106,35 @@ Echo_SendCommandEx:
     movem.l (sp)+, d0-d1            ; Restore register
     rts                             ; End of subroutine
 
+;****************************************************************************
+; Echo_SendCommandByte
+; Sends an Echo command (with a byte parameter)
+;
+; input d0.b ... Echo command
+; input d1.b ... Byte parameter
+;****************************************************************************
+
+Echo_SendCommandByte:
+    Echo_Z80Request                 ; We need the Z80 bus
+
+    move.w  d1, -(sp)               ; Save register
+@Try:
+    tst.b   ($A01FFF)               ; Check if Echo is ready
+    beq.s   @Ready                  ; Too busy?
+    Echo_Z80Release                   ; Let Echo continue
+    move.w  #$FF, d1                  ; Give it some time
+    dbf     d1, *                       ; ...
+    Echo_Z80Request                   ; Get Z80 bus back
+    bra.s   @Try                      ; Try again
+
+@Ready:
+    move.w  (sp)+, d1               ; Restore register
+    move.b  d0, ($A01FFF)           ; Write command ID
+    move.b  d1, ($A01FFC)           ; Write parameter
+    Echo_Z80Release                 ; We're done with the Z80 bus
+
+    rts                             ; End of subroutine
+
 ;****************************************************************************
 ; Echo_PlaySFX
 ; Plays a SFX
@@ -115,7 +145,7 @@ Echo_SendCommandEx:
 Echo_PlaySFX:
     move.w  d0, -(sp)               ; Save register
     move.b  #$02, d0                ; Command $02 = play SFX
-    bsr     Echo_SendCommandEx      ; Send command to Echo
+    bsr     Echo_SendCommandAddr    ; Send command to Echo
     move.w  (sp)+, d0               ; Restore register
     rts                             ; End of subroutine
 
@@ -141,7 +171,7 @@ Echo_StopSFX:
 Echo_PlayBGM:
     move.w  d0, -(sp)               ; Save register
     move.b  #$04, d0                ; Command $04 = play BGM
-    bsr     Echo_SendCommandEx      ; Send command to Echo
+    bsr     Echo_SendCommandAddr    ; Send command to Echo
     move.w  (sp)+, d0               ; Restore register
     rts                             ; End of subroutine
 
@@ -169,6 +199,21 @@ Echo_ResumeBGM:
     move.w  (sp)+, d0               ; Restore register
     rts                             ; End of subroutine
 
+;****************************************************************************
+; Echo_SetPCMRate
+; Sets the playback rate of PCM
+;
+; input d0.b ... New rate (timer A value)
+;****************************************************************************
+
+Echo_SetPCMRate:
+    movem.l d0-d1, -(sp)            ; Save registers
+    move.b  d0, d1                  ; Put parameter in place
+    move.b  #$07, d0                ; Command $07 = set PCM rate
+    bsr     Echo_SendCommandByte    ; Send command to Echo
+    movem.l (sp)+, d0-d1            ; Restore registers
+    rts                             ; End of subroutine
+
 ;****************************************************************************
 ; Echo_GetStatus
 ; Gets the current status of Echo
@@ -258,6 +303,6 @@ Echo_Init:
 ; It should be located wherever Echo_ProgFile was defined
 ;****************************************************************************
 
-@Z80Program: incbin "..."
+@Z80Program: incbin "../bin/prog-z80.bin"
 @Z80ProgSize equ *-@Z80Program
     even
-- 
cgit v1.2.3