diff --git a/avr/modules/ram/23LC512/main.asm b/avr/modules/ram/23LC512/main.asm
index f9ca8baa..2d2a73d9 100644
--- a/avr/modules/ram/23LC512/main.asm
+++ b/avr/modules/ram/23LC512/main.asm
@@ -60,11 +60,11 @@ RAM_23LC512_Init:
 ; @routine RAM_23LC512_StartWriting @global
 ;
 ; @param X destination address
-; @clobbers r16-r19, r23
+; @clobbers r16, r17, r23
 
 RAM_23LC512_StartWriting:
   ldi r16, RAM_23LC512_CMD_WRITE
-  rjmp ram23LC512StartTransfer   ; (r16-r19, r23)
+  rjmp ram23LC512StartTransfer   ; (r16, r17, r23)
 ; @end
 
 
@@ -73,11 +73,11 @@ RAM_23LC512_StartWriting:
 ; @routine RAM_23LC512_StartReading @global
 ;
 ; @param X source address
-; @clobbers r16-r19, r23
+; @clobbers r16, r17, r23
 
 RAM_23LC512_StartReading:
   ldi r16, RAM_23LC512_CMD_READ
-  rjmp ram23LC512StartTransfer   ; (r16-r19, r23)
+  rjmp ram23LC512StartTransfer   ; (r16, r17, r23)
 ; @end
 
 
@@ -85,10 +85,11 @@ RAM_23LC512_StartReading:
 ; ---------------------------------------------------------------------------
 ; @routine RAM_23LC512_EndTransfer @global
 ;
+; @clobbers none
 
 RAM_23LC512_EndTransfer:
   sbi RAMCS_OUTPUT, RAMCS_PIN     ; CS high
-  bigcall SPISW_MasterStop
+  bigcall SPISW_MasterStop        ; (none)
   ret
 ; @end
 
@@ -99,19 +100,22 @@ RAM_23LC512_EndTransfer:
 ;
 ; @param X        source address
 ; @param Y        destination address
-; @param R25:r24  number of bytes to read
-; @clobbers r16-r19, r23-r25
+; @param R17      number of bytes to read
+; @clobbers r16, r17, r23
 
 RAM_23LC512_ReadBytes:
-  rcall RAM_23LC512_StartReading  ; (r16-r19, r23)
+  push r22
+    mov r22, r17
+    rcall RAM_23LC512_StartReading  ; (r16, r17, r23)
   
 RAM_23LC512_ReadBytes_loop:
-    ldi r16, 0xff
-    bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
-    st Y+, r16
-    sbiw r25:r24, 1
-  brne RAM_23LC512_ReadBytes_loop
-  rcall RAM_23LC512_EndTransfer
+      ldi r16, 0xff
+      bigcall SPISW_MasterExchangeByteMode0 ; (r17, r23)
+      st Y+, r16
+      dec r22
+    brne RAM_23LC512_ReadBytes_loop
+    rcall RAM_23LC512_EndTransfer
+  pop r22
   ret
 ; @end
 
@@ -122,18 +126,21 @@ RAM_23LC512_ReadBytes_loop:
 ;
 ; @param X        destination address
 ; @param Y        source address
-; @param R25:r24  number of bytes to write
-; @clobbers r16-r19, r23-r25
+; @param R17      number of bytes to read
+; @clobbers r16, r17, r23
 
 RAM_23LC512_WriteBytes:
-  rcall RAM_23LC512_StartWriting  ; (r16-r19, r23)
+  push r22
+    mov r22, r17
+    rcall RAM_23LC512_StartWriting          ; (r16, r17, r23)
   
 RAM_23LC512_WriteBytes_loop:
-    ld r16, Y+
-    bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
-    sbiw r25:r24, 1
-  brne RAM_23LC512_WriteBytes_loop
-  rcall RAM_23LC512_EndTransfer
+      ld r16, Y+
+      bigcall SPISW_MasterExchangeByteMode0 ; (r17, r23)
+      dec r22
+    brne RAM_23LC512_WriteBytes_loop
+    rcall RAM_23LC512_EndTransfer           ; (none)
+  pop r22
   ret
 ; @end
 
@@ -165,23 +172,25 @@ RAM_23LC512_Fill_loop:
 ; ---------------------------------------------------------------------------
 ; @routine RAM_23LC512_WritePattern @global
 ;
-; @clobbers r16-r19, r23-r25
+; @clobbers r16, r17, r23, X
 
 RAM_23LC512_WritePattern:
-  clr xl
-  clr xh
-  rcall RAM_23LC512_StartWriting  ; (r16-r19, r23)
-  ldi r24, LOW(RAM_23LC512_PATTERNSIZE)
-  ldi r25, HIGH(RAM_23LC512_PATTERNSIZE)
-  clr xl
-  clr xh
+  push r24
+    push r25
+      clr xl
+      clr xh
+      rcall RAM_23LC512_StartWriting            ; (r16, r17, r23)
+      ldi r24, LOW(RAM_23LC512_PATTERNSIZE)
+      ldi r25, HIGH(RAM_23LC512_PATTERNSIZE)
 RAM_23LC512_WritePattern_loop:
-    mov r16, xh
-    bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
-    adiw xh:xl, 1
-    sbiw r25:r24, 1
-  brne RAM_23LC512_WritePattern_loop
-  rcall RAM_23LC512_EndTransfer
+        mov r16, xh
+        bigcall SPISW_MasterExchangeByteMode0   ; (r16, r17, r23)
+        adiw xh:xl, 1
+        sbiw r25:r24, 1
+      brne RAM_23LC512_WritePattern_loop
+      rcall RAM_23LC512_EndTransfer
+    pop r25
+  pop r24
   ret
 ; @end
 
@@ -190,28 +199,30 @@ RAM_23LC512_WritePattern_loop:
 ; ---------------------------------------------------------------------------
 ; @routine RAM_23LC512_ReadPattern @global
 ;
-; @clobbers r16-r19, r23-r25
+; @clobbers r16, r17, r23, X
 
 RAM_23LC512_ReadPattern:
-  clr xl
-  clr xh
-  rcall RAM_23LC512_StartReading  ; (r16-r19, r23)
-  ldi r24, LOW(RAM_23LC512_PATTERNSIZE)
-  ldi r25, HIGH(RAM_23LC512_PATTERNSIZE)
-  clr xl
-  clr xh
+  push r24
+    push r25
+      clr xl
+      clr xh
+      rcall RAM_23LC512_StartReading          ; (r16, r17, r23)
+      ldi r24, LOW(RAM_23LC512_PATTERNSIZE)
+      ldi r25, HIGH(RAM_23LC512_PATTERNSIZE)
 RAM_23LC512_ReadPattern_loop:
-    ldi r16, 0xff
-    bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
-    cp r16, xh
-    clc
-    brne RAM_23LC512_ReadPattern_ret
-    adiw xh:xl, 1
-    sbiw r25:r24, 1
-  brne RAM_23LC512_ReadPattern_loop
-  rcall RAM_23LC512_EndTransfer
-  sec
+        ldi r16, 0xff
+        bigcall SPISW_MasterExchangeByteMode0 ; r16=value read (r17, r23)
+        cp r16, xh
+        clc
+        brne RAM_23LC512_ReadPattern_ret
+        adiw xh:xl, 1
+        sbiw r25:r24, 1
+      brne RAM_23LC512_ReadPattern_loop
+      rcall RAM_23LC512_EndTransfer
+      sec
 RAM_23LC512_ReadPattern_ret:
+    pop r25
+  pop r24
   ret
 ; @end
 
@@ -221,13 +232,13 @@ RAM_23LC512_ReadPattern_ret:
 ; @routine RAM_23LC512_ReadModeRegister
 ;
 ; @return r16 mode register
-; @clobbers r17-r19, r23
+; @clobbers r17, r23
 
 RAM_23LC512_ReadModeRegister:
   ldi r16, RAM_23LC512_CMD_RDMR
-  rcall ram23LC512StartCommand
+  rcall ram23LC512StartCommand          ; (r16, r17, r23)
   clr r16
-  bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
+  bigcall SPISW_MasterExchangeByteMode0 ; r16=value (r17, r23)
   push r16
     rcall RAM_23LC512_EndTransfer
   pop r16
@@ -241,16 +252,16 @@ RAM_23LC512_ReadModeRegister:
 ;
 ; @param r16 command
 ; @param X address
-; @clobbers r16-r19, r23
+; @clobbers r16, r17, r23
 
 ram23LC512StartTransfer:
-  rcall ram23LC512StartCommand
+  rcall ram23LC512StartCommand          ; (r16, r17, r23)
 
   ; send address
   mov r16, xh
-  bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
+  bigcall SPISW_MasterExchangeByteMode0 ; (r16, r17, r23)
   mov r16, xl
-  bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
+  bigcall SPISW_MasterExchangeByteMode0 ; (r16, r17, r23)
   
   ret
 ; @end
@@ -261,11 +272,11 @@ ram23LC512StartTransfer:
 ; @routine ram23LC512StartCommand
 ;
 ; @param r16 command
-; @clobbers r16-r19, r23
+; @clobbers r16, r17, r23
 
 ram23LC512StartCommand:
   push r16
-    bigcall SPISW_MasterStart
+    bigcall SPISW_MasterStart   ; (none)
   pop r16
   nop
   sbi RAMCS_DDR, RAMCS_PIN      ; CS: output
@@ -273,7 +284,7 @@ ram23LC512StartCommand:
   nop
   
   ; send command
-  bigcall SPISW_MasterExchangeByteMode0 ; (r17, r18, r19, r23)
+  bigcall SPISW_MasterExchangeByteMode0 ; (r16, r17, r23)
 
   ret
 ; @end