From 9bd376464a4b2cd4871bdc4b8d389fad6920b47c Mon Sep 17 00:00:00 2001
From: Martin Preuss <martin@aquamaniac.de>
Date: Mon, 9 Sep 2024 15:49:58 +0200
Subject: [PATCH] avr: optimized cny70 module (not tested, yet).

---
 avr/modules/cny70/main.asm | 122 +++++++++++++------------------------
 1 file changed, 42 insertions(+), 80 deletions(-)

diff --git a/avr/modules/cny70/main.asm b/avr/modules/cny70/main.asm
index 787e45a..56c3313 100644
--- a/avr/modules/cny70/main.asm
+++ b/avr/modules/cny70/main.asm
@@ -19,16 +19,11 @@
 
 
 .equ CNY70_FLAGS_ADC_STARTED  = 0x01
-.equ CNY70_FLAGS_ADC_FINISHED = 0x02
-.equ CNY70_FLAGS_ADC_VALID    = 0x04
-
-.equ CNY70_TIMER_100MS        = 20 ; every 2s
-
+.equ CNY70_FLAGS_ADC_UPDATED  = 0x02
 
 cny70DataBegin:
   cny70Flags:        .byte 1
   cny70LastData:     .byte 1
-  cny70TimerCounter: .byte 1
 cny70DataEnd:
 
 
@@ -60,13 +55,16 @@ CNY70_Init:
 
   ; setup pins and interrupts
   sbi CNY70_DDR_LED, CNY70_PINNUM_LED         ; set DATA port as output
-  cbi CNY70_PORT_LED, CNY70_PINNUM_LED        ; LED off
+  sbi CNY70_PORT_LED, CNY70_PINNUM_LED        ; LED off
   cbi CNY70_PORT_ADC, CNY70_PINNUM_ADC        ; disable internal pullup for ADC
   cbi CNY70_DDR_ADC, CNY70_PINNUM_ADC         ; set ADC port as input
 
-  ldi r16, (1<<ADLAR) | (1<<CNY70_ADCSRB_ADC) ; "8 bit" mode, disable digital pin input buffer 
+  ldi r16, (1 << CNY70_MUX_ADC) ; select input pin, use Vcc as reference voltage
+  out ADMUX, r16
+  sbi ADCSRB, ADLAR ; left shift result for 8-bit representation in ADCH
+  ldi r16, (1 << ADEN) | (1 << ADPS1) | (1 << ADPS0) ; enable, prescaler 8
   out ADCSRB, r16
-
+  
   sec
   ret
 
@@ -79,92 +77,56 @@ CNY70_Fini:
 
 
 CNY70_Run:
+  ret ; DEBUG (doesn't change things)
+  lds r16, cny70Flags
+  andi r16, CNY70_FLAGS_ADC_UPDATED ; new value?
+  breq CNY70_Run_done               ; nope, jump
+  rcall CNY70_SendAdc               ; send value
+  brcc CNY70_Run_done               ; jump on error
+  lds r16, cny70Flags               ; value sent, clear flag
+  andi r16, ~CNY70_FLAGS_ADC_UPDATED
+  sts cny70Flags, r16
+CNY70_Run_done:
+  clc
   ret
 
 
 
-CNY70_Every100ms:
-  push r15
-    in r15, SREG
-    cli
-    lds r16, cny70Flags
-    andi r16, CNY70_FLAGS_ADC_STARTED
-    brne CNY70_Every100ms_done
-    
-    lds r16, cny70TimerCounter
-    inc r16
-    cpi r16, CNY70_TIMER_100MS
-    brcc CNY70_Every100ms_startConversion
-    sts cny70TimerCounter, r16
-    rjmp CNY70_Every100ms_done
-
-CNY70_Every100ms_startConversion:
-    clr r16
-    sts cny70TimerCounter, r16
-    rcall cny70StartConversion
-CNY70_Every100ms_done:
-    out SREG, r15
-  pop r15
+CNY70_OnTimer:
+  lds r16, cny70Flags
+  andi r16, CNY70_FLAGS_ADC_STARTED
+  breq CNY70_OnTimer_startConversion
+  ; conversion is running, complete?
+  sbis ADCSRA, ADSC
+  ret ; only if bit clear
+  
+  ; conversion complete, read value, set flags
+  lds r16, cny70Flags
+  andi r16, ~CNY70_FLAGS_ADC_STARTED
+  ori r16, CNY70_FLAGS_ADC_UPDATED
+  sts cny70Flags, r16
+  in r16, ADCH                         ; read value from ADC
+  sts cny70LastData, r16
+  sbi CNY70_PORT_LED, CNY70_PINNUM_LED ; LED off
+  nop
+  nop
+  nop
   ret
 
-
-
-cny70StartConversion:
-  sbi CNY70_PORT_LED, CNY70_PINNUM_LED ; LED on
+CNY70_OnTimer_startConversion:
+  lds r16, cny70Flags
+  ori r16, CNY70_FLAGS_ADC_STARTED
+  sts cny70Flags, r16
+  cbi CNY70_PORT_LED, CNY70_PINNUM_LED ; LED on
   nop
   nop
   nop
-  ; setup adc
-  ldi r16, CNY70_MUX_ADC
-  out ADMUX, r16
-  ; enable adc, enable irq, clear irq, select prescaler 8 (125kHz)
-  ldi r16, (1<<ADEN) | (1<<ADIE) | (1<<ADIF) | (1<<ADPS1) | (1<<ADPS0)
-  out ADCSRA, r16
-
   sbic ADCSRA, ADSC ; start conversion
-
-  push r15
-    in r15, SREG
-    cli
-    lds r16, cny70Flags
-    ori r16, CNY70_FLAGS_ADC_STARTED
-    andi r16, ~CNY70_FLAGS_ADC_FINISHED
-    sts cny70Flags, r16
-    out SREG, r15
-  pop r15
   ret
 
 
 
-cny70Isr:
-  push r15
-    in r15, SREG
-    push r16
-      cbi CNY70_PORT_LED, CNY70_PINNUM_LED ; LED off
-      in r16, ADCH
-      sts cny70LastData, r16    ; store value
-      clr r16                   ; disable ADC
-      out ADCSRA, r16
-      lds r16, cny70Flags
-      ori r16, CNY70_FLAGS_ADC_FINISHED | CNY70_FLAGS_ADC_VALID
-      andi r16, ~CNY70_FLAGS_ADC_STARTED
-      sts cny70Flags, r16
-    pop r16
-    out SREG, r15
-  pop r15
-  reti
-
-
-
-
-
 CNY70_SendAdc:
-  lds r16, cny70Flags
-  andi r16, CNY70_FLAGS_ADC_VALID
-  brne CNY70_SendAdc_haveValue
-  sec
-  ret
-CNY70_SendAdc_haveValue:
   ldi r16, 0xff                      ; destination address
   ldi r17, VALUE_ID_ADC              ; value id
   ldi r22, AQHOME_VALUETYPE_UNKNOWN