From b65a0249a5e10e7b9b73ef1aaa5fa91a2f88e779 Mon Sep 17 00:00:00 2001
From: "matthias@arch" <matthias.quintern@posteo.de>
Date: Sun, 31 Dec 2023 01:56:42 +0100
Subject: [PATCH] use masked writes for RA

---
 system/lcd.s65 | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/system/lcd.s65 b/system/lcd.s65
index 6912da7..b5222f5 100644
--- a/system/lcd.s65
+++ b/system/lcd.s65
@@ -22,9 +22,9 @@ charcount:  .res 1
     lda #$ff                        ; RB 0-7 output
     sta lcd::LCD_IO+IO::DDRB
 
-    MaskedWrite lcd::LCD_IO+IO::DDRA, #(lcd::RS | lcd::RW | lcd::E), #lcd::RA_MASK
-    ; lda #(lcd::RS | lcd::RW | lcd::E)   ; RA 5-7 output
-    ; sta lcd::LCD_IO+IO::DDRA
+    lda lcd::LCD_IO+IO::DDRA
+    ora #(lcd::RS | lcd::RW | lcd::E)
+    sta lcd::LCD_IO+IO::DDRA
 
     ; init lcd
     lda #lcd::CMD_FUNCTION_SET  
@@ -176,26 +176,31 @@ charcount:  .res 1
 .proc _wait_nbusy
     pha
     stz lcd::LCD_IO + IO::DDRB           ; set IO1-IO + IO::RB to input
-@lcd_wait_nbusy_loop:   ; read the busy flag
-    ; TODO use update_with_mask
-    lda #lcd::RW
+    lda lcd::LCD_IO + IO::RA
+    and #<~lcd::RA_MASK
+    ora #lcd::RW
     sta lcd::LCD_IO + IO::RA
-    lda #(lcd::RW | lcd::E)
+
+@lcd_wait_nbusy_loop:   ; read the busy flag
+    ; set E low, then high
+    lda lcd::LCD_IO + IO::RA
+    and #<~lcd::E
+    sta lcd::LCD_IO + IO::RA
+    ora #lcd::E
     sta lcd::LCD_IO + IO::RA
     
     lda lcd::LCD_IO + IO::RB
     bmi @lcd_wait_nbusy_loop   ; msb set
-    ; and #%10000000      ; and updates zero flag, if not set retry
-    ; bne @lcd_wait_nbusy_loop
     
-    lda #%00000000      ; TODO dont overwrite 0-4
+    lda lcd::LCD_IO + IO::RA
+    and #<~lcd::RA_MASK
     sta lcd::LCD_IO + IO::RA
     lda #%11111111   ; set IO1-IO + IO::RB to output
     sta lcd::LCD_IO + IO::DDRB
     pla
     rts
 .endproc
-    
+
 
 ;;********************************************************************************
 ;; @function Send a command to the lcd