From 50a3d3a7c8d25c09048ceec99b82911b335eaaac Mon Sep 17 00:00:00 2001
From: Nidan <nidan@ghostdub.de>
Date: Sat, 14 Jan 2012 01:19:02 +0100
Subject: [PATCH] removed some unnecessary bitshifts in mmc code, a bit of
 cleaning in gg.c, documented pin usage in README

---
 README | 15 +++++++++++++++
 gg.c   | 28 +++++++++++++---------------
 mmc.c  | 11 ++++-------
 3 files changed, 32 insertions(+), 22 deletions(-)

diff --git a/README b/README
index ef50282..7f0a740 100644
--- a/README
+++ b/README
@@ -1,3 +1,18 @@
 
+pin belegung:
+
+PA0 - MMC - 
+PA1 - MMC - 
+PA2 - MMC - 
+PA3 - MMC - 
+
+PA7 - "Ausschalter"
+
+PB0 - Progger - MOSI
+PB1 - Progger - MISO
+PB2 - Progger - SCK
+
+PB7 - Reset
+
 
 mmc-code from http://www.ulrichradig.de/home/index.php/avr/mmc-sd
diff --git a/gg.c b/gg.c
index c0f0ac3..3f78dd8 100644
--- a/gg.c
+++ b/gg.c
@@ -26,16 +26,10 @@ void timer_init_tiny26(void)
 	TIMSK = 1 << TOIE1;/* interrupt on overflow */
 }
 
-
-uint8_t length[4];/* remaining samples */
-uint32_t mmc_position;/* current reading position on mmc */
-
-uint8_t overflows = 1;/* remaining counter overflows until next sample */
-#define SAMPLE_BITS 11
-ringbuf_t rb;
-
 #define BUFFER_SIZE 32
 uint16_t buffer[BUFFER_SIZE];/* buffer for mmc data */
+ringbuf_t rb;
+uint32_t length;/* remaining samples */
 
 /*ISR(TIMER1_OVF1_vect, ISR_NAKED)
 {
@@ -52,7 +46,7 @@ uint16_t buffer[BUFFER_SIZE];/* buffer for mmc data */
     }
     __asm__("out 0x3f,r2"); // restore sreg
     reti();
-}//*/
+}// */
 
 ISR(TIMER1_OVF1_vect){
     // next try: simplistic, not too much looking at speed
@@ -61,26 +55,30 @@ ISR(TIMER1_OVF1_vect){
     if(--cnt_to_next){
         ringbuf_get(&rb, &next);
         OCR1A = next>>8;
-        cnt_to_ocr_incr = 7-(next & 0x7);        
+        cnt_to_ocr_incr = 7-(next & 0x7);
         cnt_to_next = 7;
+        if(!--length)
+        {
+        	/* shut down */
+        	PORTA &= ~(1 << PA7);
+        }
     } else {
         if(--cnt_to_ocr_incr){
            OCR1A += 1;
         }
     }
-} 
-        
-
-
+}
 
 
 int main(void) __attribute__((noreturn));
 int main(void)
 {
+	DDRA |= (1 << PA7);
+	PORTA |= (1 << PA7);
 	ringbuf_init(&rb, buffer, BUFFER_SIZE);
 	if(mmc_init() != 0) {/* mmc fail */;}
 	
-	mmc_read_part(0, length, 4);
+	mmc_read_part(0, (unsigned char *) &length, 4);
 	
 	timer_init_tiny26();
 	sei();
diff --git a/mmc.c b/mmc.c
index 7df9a42..11e6808 100644
--- a/mmc.c
+++ b/mmc.c
@@ -145,12 +145,9 @@ unsigned char mmc_read_byte (void)
 		
 		if(bit_is_set(MMC_Read,SPI_DI) > 0) //Lesen des Pegels von MMC_DI
 		{
-			Byte |= (1<<(a-1));
-		}
-		else
-		{
-			Byte &=~(1<<(a-1));
+			Byte |= 1;
 		}
+		Byte <<= 1;
 		MMC_Write |=(1<<SPI_Clock); //setzt Clock Impuls wieder auf (High)
 		WAIT_HALF_CLOCK;
 	}
@@ -168,9 +165,9 @@ void mmc_write_byte (unsigned char Byte)
 	SPDR = Byte; 	//Sendet ein Byte
 	while(!(SPSR & (1 << SPIF))) {;}//Wartet bis Byte gesendet wurde
 #else			//Routine für Software SPI
-	for(unsigned char a=8; a>0; a--) //das Byte wird Bitweise nacheinander Gesendet MSB First
+	for(uint8_t current_bit = 1 << 7; current_bit; current_bit >>= 1) //das Byte wird Bitweise nacheinander Gesendet MSB First
 	{
-		if(bit_is_set(Byte,(a-1))>0)	//Ist Bit a in Byte gesetzt
+		if(Byte & current_bit)	//Ist Bit a in Byte gesetzt
 		{
 			MMC_Write |= (1<<SPI_DO); //Set Output High
 		}