send and receive works

2 files changed, 80 insertions, 84 deletions

diff --git a/Makefile b/Makefile
index e8d729a..2bbd104 100644
--- a/Makefile
+++ b/Makefile
@@ -81,7 +81,7 @@ ASRC =
 # Optimization level, can be [0, 1, 2, 3, s]. 
 #     0 = turn off optimization. s = optimize for size.
 #     (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
-OPT = s
+OPT = 2
 
 
 # Debugging format.
diff --git a/main.c b/main.c
index 8cf43a1..64b811d 100644
--- a/main.c
+++ b/main.c
@@ -3,69 +3,21 @@
 
 static char buffer[300];
 
-#define OUT0 "sbi %0, 5 \n"  /* pull line to GND */
-#define OUT1 "cbi %0, 5 \n"  /* tristate the line */
+#define OUT0 "sbi %2, 5 \n"  /* pull line to GND */
+#define OUT1 "cbi %2, 5 \n"  /* tristate the line */
 
 #define WAIT10 "ldi r16, 1 \n rcall delay_loop \n"
 #define WAIT34 "ldi r16, 9 \n rcall delay_loop \n"
 #define WAIT10MINUS10 ""
 #define WAIT34MINUS10 "ldi r16,5 \n rcall delay_loop \n nop \n nop \n"
 
-int recv_gc()
+
+int send_recv_gc(char* bytes, int len)
 {
 	char* buf_ptr = buffer;
 
-	asm volatile(
-		"clr r16 \n"
-		"recv_wait_low_initial_loop: \n"
-		"inc r16 \n"
-		"breq timeout \n"
-		"sbic %1, 5 \n"
-		"rjmp recv_wait_low_initial_loop \n" // from low to the start of counting: 6 cycles = 0.5us
-		"nop \n"
-		"nop \n"
-		"nop \n"
-		"nop \n"
-
-
-		"recv_loop: \n"
-		"recv_low_begin: \n"
-		"ldi r16, 128 \n" // 1
-		"recv_low_loop: \n"
-		"inc r16 \n"      // 1
-		"breq timeout \n" // 1 if no timeout
-		"sbis %1, 5 \n"   // 1               // von high auf dec: 6
-		"rjmp recv_low_loop \n\n" // 2 if executed, 1 if skipped.
-		"nop \n"          // to account for the rjmp recv_loop below.
-		"nop \n"
-		"nop \n"
-		"nop \n"
+	/****** SEND PART ******/
 
-		"recv_high_begin: \n"
-		"nop \n" // to account for the ldi in recv_low_begin.
-		"recv_high_loop: \n"
-		"dec r16 \n" // 1
-		"breq timeout \n" // 1 if no timeout
-		"sbic %1, 5 \n" // 1                 // von low auf inc: 6
-		"rjmp recv_high_loop \n\n" // 2 if executed, 1 if skipped
-
-		"st z+, r16 \n" // 2
-		"rjmp recv_loop \n\n" // 2
-
-		"timeout: \n"
-
-		:       "+z" ((unsigned char volatile*) buf_ptr)
-		:	"I" (_SFR_IO_ADDR(PINC))
-		: "r16", "memory"
-		);
-
-		return buf_ptr-buffer;
-
-		// a value of >=128 means "0", <127 means "1" bit.
-}
-
-void send_gc(char* bytes, int len)
-{
 	int k=0;
 	for (int i=0; i<len; i++)
 		for (int j=0x80; j!=0; j=j>>1, k++)
@@ -74,11 +26,13 @@ void send_gc(char* bytes, int len)
 	len=len*8+1;
 	
 	asm volatile(
-		"push r31 \n"
+		"push r31   ; save Z\n"
 		"push r30 \n\n"
 
+		";;;;;;;; SEND PART ;;;;;;;;\n\n"
+
 		"send_loop:   \n"
-		"sbiw %2, 1 \n" // 2
+		"sbiw %3, 1 \n" // 2
 		"breq send_done \n" // 1 if not done, 2 if done
 		"ld r16, z+ \n" // 2
 		"tst r16 \n" // 1
@@ -109,11 +63,11 @@ void send_gc(char* bytes, int len)
 		"; now send the stop bit and release the line \n"
 		"nop \n nop \n nop \n"
 		OUT0
-		"; instead of WAIT10, do some sensible cleanup work \n"
-		"clr r16  ; needed below \n"
-		"pop r30 \n"
-		"pop r31 \n"
-		"nop \n nop \n nop \n nop \n nop \n"
+		"; instead of WAIT10, do sensible work \n"
+		"pop r30    ; restore Z \n"          // 2
+		"pop r31 \n"                         // 2
+		"clr r16 \n"                         // 1
+		"nop \n nop \n nop \n nop \n nop \n" // 5
 		OUT1
 		"; done :) \n\n\n"
 
@@ -121,19 +75,62 @@ void send_gc(char* bytes, int len)
 		"; now the final thing is to wait for DATA become high again (should be immediately anyway) \n"
 		"send_final_loop: \n"
 		"inc r16 \n"
-		"breq send_timeout \n"
-		"sbis %0, 5 \n"
-		"rjmp send_final_loop \n"
-		"send_timeout: \n"
-		
-		: 
-		:	"I" (_SFR_IO_ADDR(DDRC)), 
-			"I" (_SFR_IO_ADDR(PINC)),
-			"w" (len),
-			"z" ((unsigned char volatile*) buffer)
-		: "r16"
+		"breq timeout \n"
+		"sbis %1, 5 \n"
+		"rjmp send_final_loop \n\n\n"
+
+
+
+		";;;;;;;; RECEIVE PART ;;;;;;;;\n\n"
+
+
+		"clr r16 \n"
+		"recv_wait_low_initial_loop: \n"
+		"inc r16 \n"
+		"breq timeout \n"
+		"sbic %1, 5 \n"
+		"rjmp recv_wait_low_initial_loop \n" // from low to the start of counting: 6 cycles = 0.5us
+		"nop \n"
+		"nop \n"
+		"nop \n"
+		"nop \n"
+
+
+		"recv_loop: \n"
+		"recv_low_begin: \n"
+		"ldi r16, 128 \n" // 1
+		"recv_low_loop: \n"
+		"inc r16 \n"      // 1
+		"breq timeout \n" // 1 if no timeout
+		"sbis %1, 5 \n"   // 1               // von high auf dec: 6
+		"rjmp recv_low_loop \n\n" // 2 if executed, 1 if skipped.
+		"nop \n"          // to account for the rjmp recv_loop below.
+		"nop \n"
+		"nop \n"
+		"nop \n"
+
+		"recv_high_begin: \n"
+		"nop \n" // to account for the ldi in recv_low_begin.
+		"recv_high_loop: \n"
+		"dec r16 \n" // 1
+		"breq timeout \n" // 1 if no timeout
+		"sbic %1, 5 \n" // 1                 // von low auf inc: 6
+		"rjmp recv_high_loop \n\n" // 2 if executed, 1 if skipped
+
+		"st z+, r16 \n" // 2
+		"rjmp recv_loop \n\n" // 2
+
+		"timeout: \n"
+		:	"+z" ((unsigned char volatile*) buf_ptr)
+		:	"I" (_SFR_IO_ADDR(PINC)), 
+			"I" (_SFR_IO_ADDR(DDRC)),
+			"w" (len)
+		: "r16", "memory"
 		);
 
+		return buf_ptr-buffer;
+
+		// a value of >=128 means "0", <127 means "1" bit.
 }
 
 
@@ -158,14 +155,6 @@ int main (void)
 			//PORTB=~(1 << ((temp>>9)%6));
 			PORTB=~temp;
 		}
-		else if (!(PIND & 0x10))
-		{
-			//PORTB=~buffer[4];
-			char tmp=0;
-			for (int i=0;i<8;i++)
-				tmp|= ( (buffer[i]&0x80)?(1<<i):0 );
-			PORTB=~tmp;
-		}
 		else if (!(PIND & 0x20))
 		{
 			PORTB=~n_received>>3;
@@ -174,13 +163,20 @@ int main (void)
 		{
 			PORTB=~0x00;
 		}
-
-               _delay_ms(1);
+		else
+		{
+			//PORTB=~buffer[4];
+			char tmp=0;
+			for (int i=0;i<8;i++)
+				tmp|= ( (buffer[i]&0x80)?0:(1<<i) );
+			PORTB=~tmp;
+		}
+               
+		_delay_ms(1);
 
 	char foo[] = { 0x40, 0x03, 0x02 };
 
-	send_gc(foo, 3);
-	n_received=recv_gc();
+	n_received=send_recv_gc(foo, 3);
 
 
 	}