cleanup a bit

diff --git a/foo.S b/foo.S
index 109016d..b88b476 100644 (file)
--- a/foo.S
+++ b/foo.S
@@ -53,7 +53,6 @@ FLASHM = 0x4000
        RJMP    main
 .org 0x0002 ; INT0 interrupt
        CBI     EIMSK, 0 ; disable interrupt
-       ;TODO: can move 1 instruction here
        RJMP    wakeup
 .org 0x0008 ; TIM0_OVF interrupt
        RJMP    sample
@@ -198,7 +197,6 @@ main: ; setup routine
 
 loop:
        CPI     i2, 0x78    ; 16m23 -- one loop
-;cpi i2, 1 ;TODO:removeme
        BREQ    halt
 
        SLEEP
@@ -213,32 +211,32 @@ halt:
        CLR     i2          ; clear halt condition
 
        #define zero i2
-       OUT     TCCR0A, zero   ; https://www.avrfreaks.net/forum/oc1a-state-during-pwm-disable
-       OUT     TCCR0B, zero   ; disable timer to free audio pin for wakeup function
+       ; disable timer to free audio pin for wakeup function:
+       OUT     TCCR0A, zero
+       OUT     TCCR0B, zero
 
-       ;TODO: both of these necessary?
-       SBI     PORTB, 0    ; assert high level on pin2, so we can detect a plugged-in state as a low level.
-       SBI     PORTB, 2    ; assert high level on pin2, so we can detect a plugged-in state as a low level.
+       #define five x
+       LDI     x, 0x05
+
+       ;assert high level on pullup pins to avoid accidentally triggering INT0:
+       OUT     PORTB, five
 
        OUT     DDRB, zero  ; set all pins as input
-       ;;;OUT  PUEB, zero     ; disable pullups on all pins (already done @ init/main)
 
        ;set up INT0 to wake up when a audio sink is connected
-       SBI     EIMSK, 0     ; set-bit-0 high => enable interrupt
-       OUT     EICRA, zero  ; logical low generates INT0
+       SBI     EIMSK, 0    ; set-bit-0 high => enable interrupt
+       OUT     EICRA, zero ; logical low generates INT0
 
        ;enter power-down-mode
-       LDI     x, 0x05     ; sleep mode: power-down, enabled
-       OUT     SMCR, x
+       OUT     SMCR, five  ; sleep mode: power-down, enabled
        SLEEP
        ;OUT    SMCR, one   ; sleep mode: idle, enabled
        OUT     SMCR, zero  ; sleep mode: disabled
+       #undef five
 
        RJMP loop
 
 wakeup:
-       ;;;SBI  PCIFR, 1    ; clear interrupt (handled by reti)
-       ;;;OUT  PUEB, zero  ; remove pullups (already in main)
        LDI     x, 0x03     ; restore output pins
        OUT     DDRB, x
        LDI     x, 0x81