From f3630835f2a89bf93771d3193557f2abc1d7cb4d Mon Sep 17 00:00:00 2001
From: Martin Preuss <martin@aquamaniac.de>
Date: Sat, 4 Feb 2023 00:56:59 +0100
Subject: [PATCH] Utils: added code to write FLASH (bot tested, yet).

---
 avr/utils.asm | 107 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 102 insertions(+), 5 deletions(-)

diff --git a/avr/utils.asm b/avr/utils.asm
index ab70c33..60f361b 100644
--- a/avr/utils.asm
+++ b/avr/utils.asm
@@ -1,6 +1,7 @@
 
 
 
+; ---------------------------------------------------------------------------
 ; Utils_WaitNanoSecs  waittime_in_ns , cyles_already_used , waitcount_register 
 ;
 ;     cycles already used will be subtracted from the delay
@@ -42,7 +43,7 @@
 
 
 
-; ***************************************************************************
+; ---------------------------------------------------------------------------
 ; Utils_FillSram
 ;
 ; IN:
@@ -66,7 +67,7 @@ Utils_FillSram_end:
 
 
 
-; ***************************************************************************
+; ---------------------------------------------------------------------------
 ; Increment a 32 bit counter at the address given by X.
 ; IN:
 ; - X: Address of the 4 byte counter (1. byte is LSB)
@@ -93,7 +94,7 @@ Utils_IncrementCounter32:
 
 
 
-; ***************************************************************************
+; ---------------------------------------------------------------------------
 ; Increment a 16 bit counter at the address given by X.
 ; IN:
 ; - X: Address of the 2 byte counter (1. byte is LSB)
@@ -115,7 +116,7 @@ Utils_IncrementCounter16:
 
 
 
-; ***************************************************************************
+; ---------------------------------------------------------------------------
 ; Utils_ReadEeprom
 ;
 ; Read a byte from EEPROM (see example in ATtiny24/44/84 manual p.19).
@@ -137,7 +138,7 @@ Utils_ReadEeprom:
 
 
 
-; ***************************************************************************
+; ---------------------------------------------------------------------------
 ; Utils_WriteEeprom
 ;
 ; Write a byte to EEPROM (see example in ATtiny24/44/84 manual p.18).
@@ -166,3 +167,99 @@ Utils_WriteEeprom:
 
 
 
+; ---------------------------------------------------------------------------
+; Utils_ReadFlashPageIntoPageBuffer
+;
+;
+; IN:
+; - Z: Address to read from (byte address as for LPM!)
+; OUT:
+; - nothing
+; MODIFIED REGISTERS: R0, R1, R15, R16, R20, R24, R25, Z
+
+Utils_ReadFlashPageIntoPageBuffer:
+  in r15, SREG
+  cli
+    ldi r24, LOW(PAGESIZE*2)
+    ldi r25, HIGH(PAGESIZE*2)
+Utils_ReadFlashPageIntoPageBuffer_loop:
+      lpm r0, Z+                                ; read source data from FLASH (low)
+      lpm r1, Z                                 ; read source data from FLASH (high)
+      sbiw ZH:ZL, 1                             ; rewind Z address for following SPM
+      ldi r20, (1<<SPMEN)                       ; enable next SPM, write into temp page buffer
+      rcall utilsDoSpm                          ; (R16)
+      adiw ZH:ZL, 2
+      sbiw r25:r24, 2                           ;use subi for PAGESIZEB<=256
+    brne Utils_ReadFlashPageIntoPageBuffer_loop
+  out SREG, r15
+  ret
+
+
+
+; ---------------------------------------------------------------------------
+; Utils_EraseFlashPage
+;
+;
+; IN:
+; - Z: Address of the page to erase.
+; OUT:
+; - nothing
+; MODIFIED REGISTERS: R0, R1, R15, R16, R18, R19, R20
+
+Utils_EraseFlashPage:
+  in r15, SREG
+  cli
+    ldi r20, (1<<PGERS) + (1<<SPMEN)          ; enable next SPM, erase page (R1/R0 ignored)
+    rcall utilsDoSpm                          ; (R16)
+  out SREG, r15
+  ret
+
+
+
+; ---------------------------------------------------------------------------
+; Utils_WriteFlashPage
+;
+;
+; IN:
+; - Z: Address of the page to erase.
+; OUT:
+; - nothing
+; MODIFIED REGISTERS: R0, R1, R15, R16, R18, R19, R20
+
+Utils_WriteFlashPage:
+  in r15, SREG
+  cli
+    ldi r20, (1<<PGWRT) + (1<<SPMEN)          ; enable next SPM, erase page (R1/R0 ignored)
+    rcall utilsDoSpm                          ; (R16)
+  out SREG, r15
+  ret
+
+
+
+; ---------------------------------------------------------------------------
+; utilsDoSpm
+;
+; 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
+
+utilsDoSpm:
+wait:                ; wait for possibly previous SPM to complete
+    in r16, SPMCSR
+    sbrc r16, SPMEN
+  rjmp wait
+  ; SPM timed sequence
+  out SPMCSR, r20
+  spm
+  ret
+
+
+
+