Added notes and comments; halved blinking rate in blink.asm

lab2/blink.asm

@@ -1,22 +1,24 @@
-
-
 .include "msp430g2553.inc"
 
   org 0xC000
 start:
-  ;mov.w #0x5a80, &WDTCTL
+  ;mov.w #0x5a80,       &WDTCTL
   mov.w #WDTPW|WDTHOLD, &WDTCTL
-  mov.b #0x41, &P1DIR
-  mov.w #0x01, r8
+  mov.b #0x41,          &P1DIR    ; #01000001b (P1.6 == LED2, P1.0 == LED1)
+  mov.w #0x01,          r8        ; #00000001b (start on LED1)
 repeat:
-  mov.b r8, &P1OUT
-  xor.b #0x41, r8
-  mov.w #40000, r9
-waiter:
+  mov.b r8,     &P1OUT
+  xor.b #0x41,  r8      ; #00000001b -> #01000000b -> ... (LED0 -> LED1 -> ...)
+  mov.w #40000, r9      ; counts to decrement before blink
+  mov.w #40000, r10     ; counts to decrement (2nd dec, since 16-bit max value is 65536)
+waiter1:
   dec r9
-  jnz waiter
-  jmp repeat
+  jnz waiter1           ; r9 not yet 0
+waiter2:
+  dec r10
+  jnz waiter2           ; r10 not yet 0
+  jmp repeat            ; r9, r10 == 0; blink other LED
 
   org 0xfffe
-  dw start             ; set reset vector to 'init' label
+  dw  start             ; set reset vector to 'init' label
 

lab2/blink.hex

@@ -1,4 +1,5 @@
 :10C00000B240805A2001F240410022001843C24849
-:10C01000210078E041003940409C1983FE23F73F1E
+:10C01000210078E041003940409C3A40409C19831F
+:08C02000FE231A83FE23F33F07
 :02FFFE0000C041
 :00000001FF

lab2/lab2.asm

@@ -8,12 +8,17 @@ START:
     mov.b   #11110111b,     &P1DIR
 
     ; set digits
+   ;mov.b   #DDDDxAASb      &P1OUT  ; DDDD (alternate from S = 0 to S = 1 to strobe)
+
     mov.b   #01100000b,     &P1OUT  ; xxx6
     mov.b   #01100001b,     &P1OUT  ; xxx6
+
     mov.b   #01000010b,     &P1OUT  ; xx46
     mov.b   #01000011b,     &P1OUT  ; xx46
+
     mov.b   #00010100b,     &P1OUT  ; x146
     mov.b   #00010101b,     &P1OUT  ; x146
+
     mov.b   #01000110b,     &P1OUT  ; 4146
     mov.b   #01000111b,     &P1OUT  ; 4146
 

lab2/lab2.hex

@@ -1,6 +1,6 @@
 :10C0000031400004B240805A2001F240F700220083
-:10C01000F24060002100F24061002100F240420045
-:10C020002100F24043002100F24014002100F240C0
+:10C01000F24060002100F24061002100F240C200C5
+:10C020002100F240C3002100F24014002100F24040
 :10C0300015002100F24046002100F2404700210097
 :04C0400032D01000EA
 :02FFFE0000C041

lab2/lab2_notes.txt

@@ -0,0 +1,11 @@
+Commands:
+    - Compile .asm to .hex: `naken430asm -o <name>.hex <name>.asm`
+    - Flash to microprocessor: `mspdebug rf2500`, then enter `prog <name>.hex`
+
+Note to self:
+    - microprocessor should be grounded; do NOT connect voltage to VCC!
+    - remember to connect +5V to 7-segment display
+    - connect all wires to microprocessor, then flash, then exit mspdebug!!
+      program will not run without exiting
+    - max value of a word is 2^16 = 65536, so halving blink rate by double dec count of 40000
+      means adding another decrementation of 40000 in another register