mirror of https://github.com/cc65/cc65.git
256 lines
5.6 KiB
ArmAsm
256 lines
5.6 KiB
ArmAsm
;****************
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; CC65 Lynx Library
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;
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; Originally by Bastian Schick
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; http://www.geocities.com/SiliconValley/Byte/4242/lynx/
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;
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; Ported to cc65 (http://www.cc65.org) by
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; Shawn Jefferson, June 2004
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;
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; Several changes,
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; Ullrich von Bassewitz, 1004-10-14
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;
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;
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;****************
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;* EEPROM-routs
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;* for 93C46 (1024bit => 64 16-bit words)
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;*
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;* created : 11.05.95
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;* last modified :
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;*
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;* 16.02.96 leaner (thanks to Harry)
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;* 12.03.96 test for busy after write and erase (well, Harry ;)) )
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;* 22.08.97 ported to ra65 for use with cc65
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;* 02.12.97 added xref for the new ra65
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;*
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;*
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;* (c) 1995..97 Bastian Schick
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;* CS = A7 (18)
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;* CLK = A1 (11)
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;* DI/DO = AUDIN (32)
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;*
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;* And now how to contact the EEPROM :
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;*
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;* CARD
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;* PORT ----\/---- 93C46(SMD too)
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;* (18) A7 --------| CS |- +5V
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;* (11) A1 --------| CLK |- NC
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;* +---| DI |- NC
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;* (32) AUDIN ----+---| DO |- GND
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;* ----------
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;*
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;****************
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.export _lynx_eeprom_read
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.export _lynx_eeprom_write
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.export _lynx_eeprom_erase
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.import popa
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.importzp ptr1
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.include "lynx.inc"
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; ------------------------------------------------------------------------
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; EEPROM command list
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EE_C_WRITE = $40
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EE_C_READ = $80
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EE_C_ERASE = $C0
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EE_C_EWEN = $30
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EE_C_EWDS = $00
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; ------------------------------------------------------------------------
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; unsigned __fastcall__ lynx_eeprom_read (unsigned char cell);
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; /* Read a 16 bit word from the given address */
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;
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_lynx_eeprom_read:
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and #$3f
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ora #EE_C_READ
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jsr EE_Send9Bit
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lda #$a
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sta IODIR ; set AUDIN to Input
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clc
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stz ptr1
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stz ptr1+1 ; Clear result
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ldy #16-1 ; Initialize bit counter
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@L1:
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; CLK = 1
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stz RCART0
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stz RCART0
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; CLK = 0
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stz RCART0
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stz RCART0
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lda IODAT
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and #$10 ; mask bit
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adc #$f0 ; C=1 if A=$10
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rol ptr1
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rol ptr1+1 ; shifts 0 to Carry
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dey
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bpl @L1
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ldx #$1a
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stx IODIR ; set AUDIN for output
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;EE_SET_CS_LOW
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ldx #3
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stx SYSCTL1
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dex
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stx SYSCTL1
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lda ptr1
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ldy ptr1+1 ; Load result
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rts
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; ------------------------------------------------------------------------
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; unsigned __fastcall__ lynx_eeprom_erase (unsigned char cell);
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; /* Clear the word at the given address */
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;
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_lynx_eeprom_erase:
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pha ; Save argument
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lda #EE_C_EWEN ; EWEN
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jsr EE_Send9Bit
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pla ; Restore cell
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and #$3f
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ora #EE_C_ERASE ; clear cell A
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jsr EE_Send9Bit
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bra EE_wait
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; ------------------------------------------------------------------------
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; unsigned __fastcall__ lynx_eeprom_write (unsigned char cell, unsigned val);
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; /* Write the word at the given address */
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;
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_lynx_eeprom_write:
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sta ptr1
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stx ptr1+1 ; Save val into ptr1
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lda #EE_C_EWEN ; EWEN
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jsr EE_Send9Bit
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jsr popa ; Get cell
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and #$3f ; Make valid range 0..63
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ora #EE_C_WRITE ; WRITE
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jsr EE_Send9Bit
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jsr EE_Send16Bit ; Send value in ptr1
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EE_wait:
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; EE_SET_CS_HIGH
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ldx #63
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EEloop:
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stz RCART0
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stz RCART0
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dex
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bpl EEloop
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lda #$0A
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sta IODIR ; AUDIN to input
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lda #$10
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EE_wait1:
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bit IODAT ; 'til ready :D0-read is /D0-written
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beq EE_wait1
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lda #$1a ; AUDIN to output
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sta IODIR
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lda #EE_C_EWDS ; EWDS
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; bra EE_Send9Bit ; fall into
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; ------------------------------------------------------------------------
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; Send 8 bit value in A to eeprom
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EE_Send9Bit:
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; EE_SET_CS_LOW
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ldx #3
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stx SYSCTL1
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dex
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stx SYSCTL1
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; EE_SET_CS_HIGH
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ldx #63
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EEloop2:
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stz RCART0
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stz RCART0
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dex
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bpl EEloop2
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ldy #8
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sec ; start bit
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ror A
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ror A
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ror A
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ror A ; bit 8 at pos. 4
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EEloop3:
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tax
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and #$10
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ora #$b
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sta IODAT
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; CLK = 1
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stz RCART0
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stz RCART0
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; CLK = 0
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stz RCART0
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stz RCART0
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txa
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rol A
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dey
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bpl EEloop3
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lda #$b ; fnr neue EEPROMs
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sta IODAT
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rts
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; ------------------------------------------------------------------------
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; Send 16 bit value in ptr1 to eeprom
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EE_Send16Bit:
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lda ptr1+1
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ror A
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ror ptr1
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ror A
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ror ptr1
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ror A
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ror ptr1
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ldy #15
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EEloop4:
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tax
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and #$10
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ora #$b
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sta IODAT
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; CLK = 1
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stz RCART0
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stz RCART0
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; CLK = 0
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stz RCART0
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stz RCART0
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txa
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rol ptr1
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rol A
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dey
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bpl EEloop4
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; EE_SET_CS_LOW
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ldx #3
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stx SYSCTL1
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dex
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stx SYSCTL1
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lda #$b ; fnr neue EEPROMs
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sta IODAT
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rts
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