From e25b0ad69d5b17aa75c91513280ddcc74399282f Mon Sep 17 00:00:00 2001
From: Martin Preuss <martin@aquamaniac.de>
Date: Sun, 4 May 2025 03:32:53 +0200
Subject: [PATCH] avr/module/flash: unified flash code for 1p/4p devices.

AtTiny 841 erases 4 pages at once, others only erase one.
Fixed a bug: only send ONE flash response to FLASH_START!!!
---
 avr/modules/flash/defs.asm         |   2 +-
 avr/modules/flash/flash1p.asm      | 305 ++-------------------------
 avr/modules/flash/flash4p.asm      | 323 ++---------------------------
 avr/modules/flash/flashprocess.asm |  54 +++--
 avr/modules/flash/flashxp.asm      | 304 +++++++++++++++++++++++++++
 avr/modules/flash/wait.asm         |  16 +-
 6 files changed, 385 insertions(+), 619 deletions(-)
 create mode 100644 avr/modules/flash/flashxp.asm

diff --git a/avr/modules/flash/defs.asm b/avr/modules/flash/defs.asm
index 264d82d..ffc904f 100644
--- a/avr/modules/flash/defs.asm
+++ b/avr/modules/flash/defs.asm
@@ -12,7 +12,7 @@
 .equ FLASH_ERROR_NONE       = 0
 .equ FLASH_ERROR_MSGERROR   = 1
 
-.equ FLASH_RECVBUFFER_MAXLEN        = 128
+.equ FLASH_RECVBUFFER_MAXLEN        = 32
 .equ FLASH_CMD_FLASH_RSP            = 74
 
 
diff --git a/avr/modules/flash/flash1p.asm b/avr/modules/flash/flash1p.asm
index 05fcf48..9e64ffc 100644
--- a/avr/modules/flash/flash1p.asm
+++ b/avr/modules/flash/flash1p.asm
@@ -16,7 +16,7 @@
 
 .dseg
 
-  flashPageNum:     .byte 2
+  flashPageStart:   .byte 2
   flashPageBuffer:  .byte FLASH_PAGESIZE
 
 
@@ -28,253 +28,6 @@
 
 
 
-; ---------------------------------------------------------------------------
-; @routine Flash_Init
-;
-; @clobbers R16
-
-Flash_Init:
-  ldi r16, 0xff
-  sts flashPageNum, r16
-  sts flashPageNum+1, r16
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine Flash_Fini
-;
-; @clobbers (R0, R1, R16, R18, R19, R20, R21, R24, R25, X)
-
-Flash_Fini:
-  push r15
-    in r15, SREG
-    cli
-    rcall flash1pEndPage           ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
-    out SREG, r15
-  pop r15
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine Flash_WriteData
-;
-; @param Z destination address in FLASH memory (byte address as for LPM!)
-; @param Y source address
-; @param r17 number of bytes to write
-; @clobbers (R0, R1, R16, R18, R19, R20, R24, R25, X)
-
-Flash_WriteData:
-  push r15
-    in r15, SREG
-    cli
-Flash_WriteData_loop:
-      tst r17
-      breq Flash_WriteData_done
-      rcall flashWriteData       ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
-    rjmp Flash_WriteData_loop
-Flash_WriteData_done:
-    out SREG, r15
-  pop r15
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashWriteData
-;
-; Interrupts must be disabled!
-;
-; @return Z next position
-; @return R17 remainder of bytes to flash
-; @param Z position to flash data to
-; @param Y source pointer
-; @param R17 number of bytes to flash
-; @clobbers R16, R18, R24, R25, X (R0, R1, R19, R20)
-
-flashWriteData:
-  rcall flashCheckCurrentValid         ; (r18, r19)
-  brcc flashWriteData_beginPage
-
-  rcall flashWriteCheckPage            ; (r18, r19)
-  brcs flashWriteData_calcPosAndLength ; still inside current page, jump
-  rcall flash1pEndPage                 ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
-flashWriteData_beginPage:
-  rcall flash1pBeginPage               ; (r16, r24, r25, X)
-flashWriteData_calcPosAndLength:
-  rcall flashCalcPosAndLength          ; (r24, r25)
-  ; X=abs pos in buffer, r18=bytes to read, r17=bytes initially requested
-  ; prepare data for return
-  sub r17, r18                         ; r17 holds remainder
-  add zl, r18                          ; Z points to next data
-  adc zh, r18                          ; only add carry flag
-  sub zh, r18
-flashWriteData_copyLoop:
-    ld r16, Y+
-    st X+, r16
-    dec r18
-  brne flashWriteData_copyLoop
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashCalcPosAndLength
-;
-; @return X   absolute write position inside buffer
-; @return R18 bytes to write
-; @param  Z   destination pos
-; @param  R17 number of bytes to write
-; @clobbers r24, r25
-
-flashCalcPosAndLength:
-  ; calc offset into buffer
-  mov r24, zl
-  andi r24, (FLASH_PAGESIZE-1)   ; r24=rel pos inside buffer
-  ldi r25, FLASH_PAGESIZE
-  sub r25, r24                   ; r25=bytes left inside page
-  mov r18, r17
-  cp r25, r17                    ; bytes to read > bytes left in page?
-  brcc flashCalcPosAndLength_l1  ; no: jump
-  mov r18, r25                   ; yes: cut r18 to number of bytes left in page
-flashCalcPosAndLength_l1:
-  ldi xl, LOW(flashPageBuffer)   ; set X to pos within page buffer
-  ldi xh, HIGH(flashPageBuffer)
-  add xl, r24
-  adc xh, r24
-  sub xh, r24
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashWriteCheckPage
-;
-; check whether the given address is inside the current page in buffer
-;
-; @return CFLAG set if same page, cleared otherwise
-; @param Z address to write to
-; @clobbers r18, r19
-
-flashWriteCheckPage:
-  ; check low byte of page
-  mov r18, zl
-  andi r18, LOW(~(FLASH_PAGESIZE-1))
-  lds r19, flashPageNum
-  cp r18, r19
-  brne flashWriteCheckPage_ClcRet
-  ; check high byte of page
-  mov r18, zh
-  andi r18, HIGH(~(FLASH_PAGESIZE-1))
-  lds r19, flashPageNum+1
-  cp r18, r19
-  brne flashWriteCheckPage_ClcRet
-  sec
-  ret
-flashWriteCheckPage_ClcRet:
-  clc
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashCheckCurrentValid
-;
-; check whether the page buffer contains a valid page (e.g. flashPageNum is not 0xffff)
-;
-; @return CFLAG set if current page is valid, cleared otherwise
-; @clobbers r18, r19
-
-flashCheckCurrentValid:
-  lds r18, flashPageNum
-  lds r19, flashPageNum+1
-  and r18, r19
-  inc r18
-  breq flashCheckCurrentValid_ClcRet
-  sec
-  ret
-flashCheckCurrentValid_ClcRet:
-  clc
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash1pBeginPage
-;
-; Interrupts must be disabled!
-;
-; @param Z Address to read from (byte address as for LPM!)
-; @clobbers (r16, r24, r25, X)
-
-flash1pBeginPage:
-  push zl
-    push zh
-      andi zl, LOW(~(FLASH_PAGESIZE-1))
-      andi zh, HIGH(~(FLASH_PAGESIZE-1))
-      sts flashPageNum, zl
-      sts flashPageNum+1, zh
-      rcall flash1pReadPageIntoSram  ; r16, r24, r25, X, Z
-    pop zh
-  pop zl
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash1pEndPage
-;
-; Interrupts must be disabled!
-;
-; @clobbers (R0, R1, R16, R18, R19, R20, R24, R25, X)
-
-flash1pEndPage:
-  rcall flashCheckCurrentValid ; (r18, r19)
-  brcs flash1pEndPage_write
-  ret
-flash1pEndPage_write:
-  push zl
-    push zh
-      rcall flash1pWritePage  ; (r0, r1, r20, r24, r25, X, Z)
-    pop zh
-  pop zl
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash1pReadPageIntoSram
-;
-; Interrupts must be disabled!
-;
-; @param Z Address to read from (byte address as for LPM!)
-; @clobbers r16, r24, X, Z
-
-flash1pReadPageIntoSram:
-  ldi xl, LOW(flashPageBuffer)
-  ldi xh, HIGH(flashPageBuffer)
-  ldi r24, LOW(FLASH_PAGESIZE)
-flash1pReadPageIntoSram_loop:
-    lpm r16, Z+ 
-    st X+, r16
-    adiw ZH:ZL, 1
-    dec r24
-  brne flash1pReadPageIntoSram_loop
-  ret
-; @end
-
-
-
 ; ---------------------------------------------------------------------------
 ; flash1pWritePage
 ;
@@ -283,58 +36,30 @@ flash1pReadPageIntoSram_loop:
 ; @clobbers r0, r1, r20, r24, r25, X, Z
 
 flash1pWritePage:
-  lds zl, flashPageNum
-  lds zh, flashPageNum+1
-  ; erase page
-  ldi r20, (1<<PGERS) + (1<<SPMEN)          ; enable next SPM, erase page (R1/R0 ignored)
-  rcall flash1pDoSpm                        ; (R16)
+  lds zl, flashPageStart
+  lds zh, flashPageStart+1
   ; copy from SDRAM into MCUs temporary page buffer
   ldi xl, LOW(flashPageBuffer)
   ldi xh, HIGH(flashPageBuffer)
   ldi r24, LOW(PAGESIZE)
-  push zl
-    push zh
 flash1pWritePages_loop:
-        ld r0, X+                               ; read source data from buffer (low)
-        ld r1, X+                               ; read source data from buffer (high)
-        ldi r20, (1<<SPMEN)                     ; enable next SPM, write R1:R0 into temp page buffer
-        rcall flash1pDoSpm                      ; (R16)
-        adiw zh:zl, 2
-        dec r24
-      brne flash1pWritePages_loop
-    pop zh
-  pop zl
+    ld r0, X+                               ; read source data from buffer (low)
+    ld r1, X+                               ; read source data from buffer (high)
+    ldi r20, (1<<SPMEN)                     ; enable next SPM, write R1:R0 into temp page buffer
+    rcall flashDoSpm                        ; (R16)
+    adiw zh:zl, 2
+    dec r24
+  brne flash1pWritePages_loop
+
+  subi zl, LOW(PAGESIZE*2)                  ; point back to begin of page
+  sbci zh, HIGH(PAGESIZE*2)
   ; transfer data from temporary page buffer into FLASH memory
   ldi r20, (1<<PGWRT) + (1<<SPMEN)          ; enable next SPM, write page (R1/R0 ignored)
-  rcall flash1pDoSpm                        ; (R16)
+  rcall flashDoSpm                          ; (R16)
   ret
 ; @end
 
 
-
-; ---------------------------------------------------------------------------
-; flash1pDoSpm
-;
-; wait until possible previous SPM finished and then issue another SPM.
-;
-; IN:
-; - R20: value for register SPMCR
-; - R0:  low value for SPM
-; - R1:  high value for SPM
-; - Z  : address for SPM (byte address!)
-; OUT:
-; - nothing
-; REGS: R16
-
-flash1pDoSpm:
-flash1pDoSpm_wait:                ; wait for possibly previous SPM to complete
-    in r16, SPMCSR
-    sbrc r16, SPMEN
-  rjmp flash1pDoSpm_wait
-  ; SPM timed sequence
-  out SPMCSR, r20
-  spm
-  ret
-
+.equ flashWritePage = flash1pWritePage
 
 
diff --git a/avr/modules/flash/flash4p.asm b/avr/modules/flash/flash4p.asm
index 24fd0cc..39086fd 100644
--- a/avr/modules/flash/flash4p.asm
+++ b/avr/modules/flash/flash4p.asm
@@ -16,7 +16,7 @@
 
 .dseg
 
-  flashPageNum:     .byte 2
+  flashPageStart:   .byte 2
   flashPageBuffer:  .byte FLASH_PAGESIZE
 
 
@@ -29,330 +29,47 @@
 
 
 ; ---------------------------------------------------------------------------
-; @routine Flash_Init
-;
-; @clobbers R16
-
-Flash_Init:
-  ldi r16, 0xff
-  sts flashPageNum, r16
-  sts flashPageNum+1, r16
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine Flash_Fini
-;
-; @clobbers (R0, R1, R16, R18, R19, R20, R21, R24, R25, X)
-
-Flash_Fini:
-  push r15
-    in r15, SREG
-    cli
-    rcall flash4pEndPage           ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
-    out SREG, r15
-  pop r15
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine Flash_WriteData
-;
-; @param Z destination address in FLASH memory (byte address as for LPM!)
-; @param Y source address
-; @param r17 number of bytes to write
-; @clobbers (R0, R1, R16, R18, R19, R20, R24, R25, X)
-
-Flash_WriteData:
-  push r15
-    in r15, SREG
-    cli
-Flash_WriteData_loop:
-      tst r17
-      breq Flash_WriteData_done
-      rcall flashWriteData       ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
-    rjmp Flash_WriteData_loop
-Flash_WriteData_done:
-    out SREG, r15
-  pop r15
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashWriteData
-;
-; Interrupts must be disabled!
-;
-; @return Z next position
-; @return R17 remainder of bytes to flash
-; @param Z position to flash data to
-; @param Y source pointer
-; @param R17 number of bytes to flash
-; @clobbers R16, R18, R24, R25, X (R0, R1, R19, R20)
-
-flashWriteData:
-  rcall flashWriteCheckPage            ; (r18, r19)
-  brcs flashWriteData_calcPosAndLength
-  rcall flash4pEndPage                 ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
-  rcall flash4pBeginPage               ; (r16, r24, r25, X, Z)
-flashWriteData_calcPosAndLength:
-  rcall flashCalcPosAndLength          ; (r24, r25)
-  ; X=abs pos in buffer, r18=bytes to read, r17=bytes initially requested
-  ; prepare data for return
-  sub r17, r18                         ; r17 holds remainder
-  add zl, r18                          ; Z points to next data
-  adc zh, r18                          ; only add carry flag
-  sub zh, r18
-flashWriteData_copyLoop:
-    ld r16, Y+
-    st X+, r16
-    dec r18
-  brne flashWriteData_copyLoop
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashCalcPosAndLength
-;
-; @return X   absolute write position inside buffer
-; @return R18 bytes to write
-; @param  Z   destination pos
-; @param  R17 number of bytes to write
-; @clobbers r24, r25
-
-flashCalcPosAndLength:
-  ; calc offset into buffer
-  mov r24, zl
-  andi r24, (FLASH_PAGESIZE-1) ; r24=rel pos inside buffer
-  ldi r25, FLASH_PAGESIZE
-  sub r25, r24                 ; r25=bytes left inside page
-  mov r18, r17
-  cp r25, r17
-  brcc flashCalcPosAndLength_l1
-  mov r18, r25
-flashCalcPosAndLength_l1:
-  ldi xl, LOW(flashPageBuffer)
-  ldi xh, HIGH(flashPageBuffer)
-  add xl, r24
-  adc xh, r24
-  sub xh, r24
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashWriteCheckPage
-;
-; check whether the given address is inside the current page in buffer
-;
-; @return CFLAG set if same page, cleared otherwise
-; @clobbers r18, r19
-
-flashWriteCheckPage:
-  ; check low byte of page
-  mov r18, zl
-  andi r18, LOW(~(FLASH_PAGESIZE-1))
-  lds r19, flashPageNum
-  cp r18, r19
-  brne flashWriteCheckPage_ClcRet
-  ; check high byte of page
-  mov r18, zh
-  andi r18, HIGH(~(FLASH_PAGESIZE-1))
-  lds r19, flashPageNum+1
-  cp r18, r19
-  brne flashWriteCheckPage_ClcRet
-  sec
-  ret
-flashWriteCheckPage_ClcRet:
-  clc
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flashCheckCurrentValid
-;
-; check whether the page buffer contains a valid page (e.g. flashPageNum is not 0xffff)
-;
-; @return CFLAG set if current page is valid, cleared otherwise
-; @clobbers r18, r19
-
-flashCheckCurrentValid:
-  lds r18, flashPageNum
-  lds r19, flashPageNum+1
-  and r18, r19
-  inc r18
-  breq flashCheckCurrentValid_ClcRet
-  sec
-  ret
-flashCheckCurrentValid_ClcRet:
-  clc
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash4pBeginPage
-;
-; Interrupts must be disabled!
-;
-; @param Z Address to read from (byte address as for LPM!)
-; @clobbers (r16, r24, r25, X)
-
-flash4pBeginPage:
-  push zl
-    push zh
-      andi zl, LOW(~(FLASH_PAGESIZE-1))
-      andi zh, HIGH(~(FLASH_PAGESIZE-1))
-      sts flashPageNum, zl
-      sts flashPageNum+1, zh
-      rcall flash4pReadPagesIntoSram  ; r16, r24, r25, X, Z
-    pop zh
-  pop zl
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash4pEndPage
-;
-; Interrupts must be disabled!
-;
-; @clobbers (R0, R1, R16, R18, R19, R20, R24, R25, X)
-
-flash4pEndPage:
-  rcall flashCheckCurrentValid ; (r18, r19)
-  brcs flash4pEndPage_write
-  ret
-flash4pEndPage_write:
-  push zl
-    push zh
-      rcall flash4pErasePages  ; (R16, R20, Z)
-      rcall flash4pWritePages  ; (r0, r1, r20, r24, r25, X, Z)
-    pop zh
-  pop zl
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash4pReadPagesIntoSram
-;
-; Interrupts must be disabled!
-;
-; @param Z Address to read from (byte address as for LPM!)
-; @clobbers r16, r24, X, Z
-
-flash4pReadPagesIntoSram:
-  ldi xl, LOW(flashPageBuffer)
-  ldi xh, HIGH(flashPageBuffer)
-  ldi r24, LOW(FLASH_PAGESIZE)
-flash4pReadPagesIntoSram_loop:
-    lpm r16, Z+ 
-    st X+, r16
-    adiw ZH:ZL, 1
-    dec r24
-  brne flash4pReadPagesIntoSram_loop
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; @routine flash4pErasePages
-;
-; Interrupts must be disabled!
-;
-; @clobbers R16, R20, Z
-
-flash4pErasePages:
-  lds zl, flashPageNum
-  lds zh, flashPageNum+1
-  ldi r20, (1<<PGERS) + (1<<SPMEN)          ; enable next SPM, erase page (R1/R0 ignored)
-  rcall flash4pDoSpm                        ; (R16)
-  ret
-; @end
-
-
-
-; ---------------------------------------------------------------------------
-; flash4pWritePages
+; flash4pWritePage
 ;
 ; Interrupts must be disabled!
 ;
 ; @clobbers r0, r1, r20, r24, r25, X, Z
 
-flash4pWritePages:
+flash4pWritePage:
   ; copy from SDRAM into MCUs temporary page buffer
-  lds zl, flashPageNum
-  lds zh, flashPageNum+1
+  lds zl, flashPageStart
+  lds zh, flashPageStart+1
   ldi xl, LOW(flashPageBuffer)
   ldi xh, HIGH(flashPageBuffer)
   ldi r25, 4                                  ; handle 4 pages at a time
-flash4pWritePages_loop1:
+flash4pWritePage_loop1:
     ldi r24, LOW(PAGESIZE)
-flash4pWritePages_loop2:
+flash4pWritePage_loop2:
       ld r0, X+                               ; read source data from buffer (low)
       ld r1, X+                               ; read source data from buffer (high)
       ldi r20, (1<<SPMEN)                     ; enable next SPM, write R1:R0 into temp page buffer
-      rcall flash4pDoSpm                      ; (R16)
+      rcall flashDoSpm                        ; (R16)
       adiw zh:zl, 2
       dec r24
-    brne flash4pWritePages_loop2
+    brne flash4pWritePage_loop2
 
-    sbiw zh:zl, (PAGESIZE*2)                  ; point back to begin of page
-    ; transfer data from temporary page buffer into FLASH memory
-    ldi r20, (1<<PGWRT) + (1<<SPMEN)              ; enable next SPM, write page (R1/R0 ignored)
-    rcall flash4pDoSpm                            ; (R16)
-    adiw zh:zl, (PAGESIZE*2)                      ; point forward to next page
+    push zl
+      push zh
+        subi zl, LOW(PAGESIZE*2)              ; point back to begin of page
+        sbci zh, HIGH(PAGESIZE*2)
+        ; transfer data from temporary page buffer into FLASH memory
+        ldi r20, (1<<PGWRT) + (1<<SPMEN)      ; enable next SPM, write page (R1/R0 ignored)
+        rcall flashDoSpm                      ; (R16)
+      pop zh
+    pop zl
     dec r25
-  brne flash4pWritePages_loop1  
+  brne flash4pWritePage_loop1  
   ret
 ; @end
 
 
 
 
-
-
-
-
-; ---------------------------------------------------------------------------
-; flas4phDoSpm
-;
-; wait until possible previous SPM finished and then issue another SPM.
-;
-; IN:
-; - R20: value for register SPMCR
-; - R0:  low value for SPM
-; - R1:  high value for SPM
-; - Z  : address for SPM (byte address!)
-; OUT:
-; - nothing
-; REGS: R16
-
-flash4pDoSpm:
-flash4pDoSpm_wait:                ; wait for possibly previous SPM to complete
-    in r16, SPMCSR
-    sbrc r16, SPMEN
-  rjmp flash4pDoSpm_wait
-  ; SPM timed sequence
-  out SPMCSR, r20
-  spm
-  ret
-
+.equ flashWritePage = flash4pWritePage
 
 
diff --git a/avr/modules/flash/flashprocess.asm b/avr/modules/flash/flashprocess.asm
index b703996..b847451 100644
--- a/avr/modules/flash/flashprocess.asm
+++ b/avr/modules/flash/flashprocess.asm
@@ -47,11 +47,11 @@ checkFlash:
   rcall flashProcessWriteFlashReady    ; (R16, R17, R18, R19, R20, Y, Z)
   rcall ioRawSendMsg                   ; (r16, r17, X)
 
-  ldi r16, CPRO_CMD_FLASH_START
+  ldi r16, NETMSG_CMD_FLASH_START
   rcall ioWaitForGivenMsg              ; (r16, r17, r18, r19, r20, r22, X)
   brcc checkFlash_end
   
-  cpi r16, CPRO_CMD_FLASH_START
+  cpi r16, NETMSG_CMD_FLASH_START
   clc
   brne checkFlash_end                  ; no FLASH_START msg received
 
@@ -60,10 +60,6 @@ checkFlash:
   ldi xh, HIGH(flashRecvBuffer)
   rcall flashProcessHandleFlashStart
   brcc checkFlash_end
-
-  ; prepare and send response
-  clr r16
-  rcall flashProcessSendFlashResponse  ; (R15, R16, R17, R18, R19, R20, R21, R22, X)
   sec
 checkFlash_end:
   ret
@@ -77,21 +73,21 @@ checkFlash_end:
 ; handling receiving FLASH_DATA and FLASH_END messages, flash new firmware
 ;
 ; @return CFLAG set if okay, cleared otherwise
-; @clobbers r16, r20
+; @clobbers r16, r20 (R0, R1, R15, R16, R17, R18, R19, R22, R24, Z)
 
 flashProcess:
   rcall Flash_Init
 flashProcess_loop1:
     ; wait up to 10s for incoming FLASH_DATA message
-    ldi r16, CPRO_CMD_FLASH_DATA
+    ldi r16, NETMSG_CMD_FLASH_DATA
     rcall ioWaitForGivenMsg            ; (r16, r17, r18, r19, r20, r22, X)
     brcc flashProcess_end              ; no FLASH_DATA or FLASH_END msg
     ; either FLASH_DATA or FLASH_END received
     ldi xl, LOW(flashRecvBuffer)
     ldi xh, HIGH(flashRecvBuffer)
-    cpi r16, CPRO_CMD_FLASH_DATA       ; not FLASH_DATA, flashing ended/aborted
+    cpi r16, NETMSG_CMD_FLASH_DATA     ; not FLASH_DATA, flashing ended/aborted
     brne flashProcess_endReceived      ; FLASH_END received, done
-    rcall flashProcessHandleFlashData  ; (R0, R1, R15, R16, R17, R18, R19, R20, Z)
+    rcall flashProcessHandleFlashData  ; (R0, R1, R15, R16, R17, R18, R19, R20, R22, R24, Z)
   rjmp flashProcess_loop1
 flashProcess_endReceived:
   rcall flashProcessHandleFlashEnd
@@ -161,27 +157,39 @@ flashProcessCheckFlashStart_notMe:
 ;
 ; @return CFLAG set if okay, cleared otherwise
 ; @param  X  buffer containing the message
-; @clobbers R0, R1, R18, Z (R15, R16, R17, R19, R20)
+; @clobbers R0, R1, R18, Z (R15, R16, R17, R19, R20, R22, R24)
 
 flashProcessHandleFlashData:
   mov yl, xl
   mov yh, xh
-  adiw yh:yl, FLASH_MSG_OFFS_MSGLEN
-  ld r17, Y                                  ; length (subtract 6)
-  cpi r17, 6                                 ; cmd(1), src(1), addr(4)
-  brcs flashProcessHandleFlashData_badData
-  subi r17, 6                                ; remaining length
-  adiw yh:yl, FLASH_PACKET_DATA_OFFS_ADDR-FLASH_MSG_OFFS_MSGLEN
-  ld zl, Y+                                  ; address (low)
-  ld zh, Y+                                  ; address (high)
-  adiw yh:yl, 2                              ; ignore high bytes, points to first data byte now
+  ldd r17, Y+FLASH_MSG_OFFS_MSGLEN           ; msg length
+  subi r17, 6                                ; remaining length (sub cmd(1), src(1), addr(4))
+  brcs flashProcessHandleFlashData_badData   ; too few payload bytes
+  breq flashProcessHandleFlashData_badData   ; no payload bytes
+  ldd zl, Y+FLASH_PACKET_DATA_OFFS_ADDR      ; only read lower two address bytes
+  ldd zh, Y+(FLASH_PACKET_DATA_OFFS_ADDR+1)
+  adiw yh:yl, FLASH_PACKET_DATA_OFFS_ADDR+4
   rcall Flash_WriteData                      ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
   clr r16
   rjmp flashProcessHandleFlashData_sendResponse
 flashProcessHandleFlashData_badData:
   ldi r16, FLASH_ERROR_MSGERROR
 flashProcessHandleFlashData_sendResponse:
+#if 0
+  push r16
+    ; send flash message back (debugging)
+    ldi r24, 50
+    rcall flashWaitForMillisecs                ; (R22, R24)
+    ldi xl, LOW(flashRecvBuffer)
+    ldi xh, HIGH(flashRecvBuffer)
+    rcall ioRawSendPacket                      ; (r16, r17, X)
+  pop r16
+#endif
+
+  ldi r24, 50
+  rcall flashWaitForMillisecs                ; (R22, R24)
   rcall flashProcessSendFlashResponse        ; (R16, R17, R18, R19, R20, X)
+  sbi LED_PIN, LED_PINNUM                    ; toggle
   sec
   ret
 ; @end
@@ -216,7 +224,7 @@ flashProcessHandleFlashEnd:
 ; @clobbers X (R16, R17, R18, R19, R20)
 
 flashProcessSendFlashResponse:
-  ; send flash ready message
+  ; send flash response message
   ldi xl, LOW(flashSendBuffer)
   ldi xh, HIGH(flashSendBuffer)
   rcall flashProcessWriteFlashRsp  ; (R16, R17, R18, R19, R20, X)
@@ -238,7 +246,7 @@ flashProcessWriteFlashRsp:
   st X+, r18  ; dest address (unused)
   ldi r18, 3  ; msg code+src address+one payload byte
   st X+, r18  ; msg len
-  ldi r17, CPRO_CMD_FLASH_RSP
+  ldi r17, NETMSG_CMD_FLASH_RSP
   st X+, r17  ; msg code
   clr r17
   st X+, r17  ; src address (not used)
@@ -262,7 +270,7 @@ flashProcessWriteFlashReady:
   st X+, r16                          ; dest address (unused)
   ldi r16, 20                         ; msg code+src address+18 payload bytes
   st X+, r16                          ; msg len
-  ldi r16, CPRO_CMD_FLASH_READY
+  ldi r16, NETMSG_CMD_FLASH_READY
   st X+, r16                          ; msg code
   ldi r16, COM2_MAINTENANCE_ADDR
   st X+, r16                          ; src address
diff --git a/avr/modules/flash/flashxp.asm b/avr/modules/flash/flashxp.asm
new file mode 100644
index 0000000..0d30037
--- /dev/null
+++ b/avr/modules/flash/flashxp.asm
@@ -0,0 +1,304 @@
+; ***************************************************************************
+; copyright   : (C) 2025 by Martin Preuss
+; email       : martin@libchipcard.de
+;
+; ***************************************************************************
+; * This file is part of the project "AqHome".                              *
+; * Please see toplevel file COPYING of that project for license details.   *
+; ***************************************************************************
+
+
+; ***************************************************************************
+; code
+
+.cseg
+
+
+
+; ---------------------------------------------------------------------------
+; @routine Flash_Init
+;
+; @clobbers R16
+
+Flash_Init:
+  ldi r16, 0xff
+  sts flashPageStart, r16
+  sts flashPageStart+1, r16
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine Flash_Fini
+;
+; @clobbers (R0, R1, R16, R18, R19, R20, R21, R24, R25, X)
+
+Flash_Fini:
+  push r15
+    in r15, SREG
+    cli
+    rcall flashEndPage             ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
+    out SREG, r15
+  pop r15
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine Flash_WriteData
+;
+; @param Z destination address in FLASH memory (byte address as for LPM!)
+; @param Y source address
+; @param r17 number of bytes to write
+; @clobbers (R0, R1, R16, R18, R19, R20, R24, R25, X)
+
+Flash_WriteData:
+  push r15
+    in r15, SREG
+    cli
+Flash_WriteData_loop:
+      rcall flashWriteData       ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
+      tst r17
+    brne Flash_WriteData_loop
+    out SREG, r15
+  pop r15
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashWriteData
+;
+; Interrupts must be disabled!
+;
+; @return Z next dest position
+; @return Y next source position
+; @return R17 remainder of bytes to flash
+; @param Z position to flash data to
+; @param Y source pointer
+; @param R17 number of bytes to flash
+; @clobbers R16, R18, R24, R25, X (R0, R1, R19, R20)
+
+flashWriteData:
+  rcall flashCheckCurrentValid         ; (r18, r19)
+  brcc flashWriteData_beginPage        ; jump if this is the first call (no page in work)
+
+  rcall flashWriteCheckPage            ; (r18, r19)
+  brcs flashWriteData_calcPosAndLength ; still inside current page, jump
+  rcall flashEndPage                   ; (R0, R1, R16, R18, R19, R20, R24, R25, X)
+flashWriteData_beginPage:
+  rcall flashBeginPage                 ; (r16, r24, r25, X)
+flashWriteData_calcPosAndLength:
+  rcall flashCalcPosAndLength          ; r18=bytes_to_write, x=pos_in_buffer (r24, r25)
+  ; X=abs pos in buffer, r18=bytes to read, r17=bytes initially requested
+  ; prepare data for return
+  sub r17, r18                         ; r17 holds remainder
+  add zl, r18                          ; Z points to next data
+  adc zh, r18                          ; only add carry flag
+  sub zh, r18
+  ; actually write data into buffer
+flashWriteData_copyLoop:
+    ld r16, Y+
+    st X+, r16
+    dec r18
+  brne flashWriteData_copyLoop
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashCalcPosAndLength
+;
+; @param  Z   destination pos
+; @param  R17 number of bytes to write
+; @return X   absolute write position inside buffer
+; @return R18 bytes to write
+; @clobbers r24, r25
+
+flashCalcPosAndLength:
+  ; calc offset into buffer
+  mov r24, zl
+  andi r24, (FLASH_PAGESIZE-1)   ; r24=rel pos inside buffer
+  ldi r25, FLASH_PAGESIZE
+  sub r25, r24                   ; r25=bytes left inside page
+  mov r18, r17
+  cp r25, r17                    ; bytes to read > bytes left in page?
+  brcc flashCalcPosAndLength_l1  ; no: jump
+  mov r18, r25                   ; yes: cut r18 to number of bytes left in page
+flashCalcPosAndLength_l1:
+  ldi xl, LOW(flashPageBuffer)   ; set X to pos within page buffer
+  ldi xh, HIGH(flashPageBuffer)
+  add xl, r24
+  adc xh, r24
+  sub xh, r24
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashWriteCheckPage
+;
+; check whether the given address is inside the current page in buffer
+;
+; @return CFLAG set if same page, cleared otherwise
+; @param Z address to write to
+; @clobbers r18, r19
+
+flashWriteCheckPage:
+  ; check low byte of page
+  mov r18, zl
+  lds r19, flashPageStart
+  eor r18, r19
+  cbr r18, LOW(FLASH_PAGESIZE-1)
+  brne flashWriteCheckPage_ClcRet
+
+  ; check high byte of page
+  mov r18, zh
+  lds r19, flashPageStart+1
+  eor r18, r19
+  cbr r18, HIGH(FLASH_PAGESIZE-1)
+  brne flashWriteCheckPage_ClcRet
+  sec
+  ret
+flashWriteCheckPage_ClcRet:
+  clc
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashCheckCurrentValid
+;
+; check whether the page buffer contains a valid page (e.g. flashPageStart is not 0xffff)
+;
+; @return CFLAG set if current page is valid, cleared otherwise
+; @clobbers r18, r19
+
+flashCheckCurrentValid:
+  lds r18, flashPageStart
+  lds r19, flashPageStart+1
+  and r18, r19
+  inc r18
+  breq flashCheckCurrentValid_ClcRet
+  sec
+  ret
+flashCheckCurrentValid_ClcRet:
+  clc
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashBeginPage
+;
+; Interrupts must be disabled!
+;
+; @param Z Address to read from (byte address as for LPM!)
+; @clobbers (r16, r24, r25, X)
+
+flashBeginPage:
+  push zl
+    push zh
+      cbr zl, LOW(FLASH_PAGESIZE-1)
+      cbr zh, HIGH(FLASH_PAGESIZE-1)
+      sts flashPageStart, zl
+      sts flashPageStart+1, zh
+      rcall flashReadPageIntoSram  ; (r16, r24, r25, X, Z)
+    pop zh
+  pop zl
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashEndPage
+;
+; Interrupts must be disabled!
+;
+; @clobbers (R0, R1, R16, R18, R19, R20, R24, R25, X)
+
+flashEndPage:
+  rcall flashCheckCurrentValid ; (r18, r19)
+  brcs flashEndPage_write
+  ret
+flashEndPage_write:
+  push zl
+    push zh
+      rcall flashErasePage  ; (R16, R20, Z)
+      rcall flashWritePage  ; (r0, r1, r20, r24, r25, X, Z)
+    pop zh
+  pop zl
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashReadPageIntoSram
+;
+; @param Z Address to read from (byte address as for LPM!)
+; @clobbers r16, r24, X, Z
+
+flashReadPageIntoSram:
+  ldi xl, LOW(flashPageBuffer)
+  ldi xh, HIGH(flashPageBuffer)
+  ldi r24, LOW(FLASH_PAGESIZE)
+flashReadPageIntoSram_loop:
+    lpm r16, Z+ 
+    st X+, r16
+;    adiw ZH:ZL, 1
+    dec r24
+  brne flashReadPageIntoSram_loop
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashErasePage
+;
+; Interrupts must be disabled!
+;
+; @clobbers R16, R20, Z
+
+flashErasePage:
+  lds zl, flashPageStart
+  lds zh, flashPageStart+1
+  ldi r20, (1<<PGERS) + (1<<SPMEN)          ; enable next SPM, erase page (R1/R0 ignored)
+  rcall flashDoSpm                          ; (R16)
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashDoSpm
+;
+; wait until possible previous SPM finished and then issue another SPM.
+;
+; @param R20 value for register SPMCR
+; @param R0  low value for SPM
+; @param R1  high value for SPM
+; @param Z   address for SPM (byte address!)
+; @clobbers R16
+
+flashDoSpm:
+flashDoSpm_wait:         ; wait for possibly previous SPM to complete
+    in r16, SPMCSR
+    sbrc r16, SPMEN
+  rjmp flashDoSpm_wait
+  ; SPM timed sequence
+  out SPMCSR, r20
+  spm
+  ret
+; @end
+
+
diff --git a/avr/modules/flash/wait.asm b/avr/modules/flash/wait.asm
index d62668c..c4ddc79 100644
--- a/avr/modules/flash/wait.asm
+++ b/avr/modules/flash/wait.asm
@@ -68,13 +68,25 @@ flashWaitForMulti100ms_loop:
 
 flashWaitFor100ms:
   ldi r24, 100
-flashWaitFor100ms_loop:
+  rjmp flashWaitForMillisecs
+
+
+
+; ---------------------------------------------------------------------------
+; @routine flashWaitForMillisecs
+; wait for multiples of 100 milliseconds.
+;
+; @param R24  time to wait in milliseconds
+; @clobbers R24 (R22)
+
+flashWaitForMillisecs:
     push r24
       rcall flashWaitFor1ms      ; (R22, R24)
     pop r24
     dec r24
-  brne flashWaitFor100ms_loop
+  brne flashWaitForMillisecs
   ret
+; @end