fixed a few spi weaknesses, like timing in spi_mst_start_packet

firmware/shared/spi.c

@@ -2,6 +2,7 @@
 #include <stdint.h>
 #include <math.h>
 #include <avr/interrupt.h>
+#include <util/delay.h>
 
 
 #include "main.h"
@@ -16,7 +17,6 @@
 
 uint8_t readbuf[5];
 uint8_t writebuf[5];
-uint8_t writebuf2[5] = {2, 4, 6, 0x12, 5};
 uint8_t pos;
 
 
@@ -84,12 +84,15 @@ void spi_init(){
 void spi_mst_start_packet(){
 #ifdef SPI_MASTER
 	SPI_SSOUT &= ~(_BV(SPI_SS_PIN));
+	_delay_us(1e6/SPI_BAUDRATE);
 #endif
 }
 
 void spi_mst_end_packet(){
 #ifdef SPI_MASTER
+	_delay_us(1e6/SPI_BAUDRATE);
 	SPI_SSOUT |= _BV(SPI_SS_PIN);
+	_delay_us(1e6/SPI_BAUDRATE);
 #endif
 }
 
@@ -125,7 +128,7 @@ void spi_mst_write_read(uint8_t len, uint8_t *data){
 
 void spi_sla_handle_packet(){
         // TODO: make slave not hangup in case of partial read
-	uint8_t opcode, addr, do_write;
+	uint8_t opcode, addr;
 	uint16_t data, newdata;
 	writebuf[0] = 0; // generate invalid replies, so no inconsistent packets
 						// are sent.

firmware/shared/spi_proto.c

@@ -7,7 +7,7 @@ uint8_t mst_buf[5];
 
 uint16_t spi_master_transceive(uint8_t opcode, uint8_t addr, uint16_t value)
 {
-	do{
+//	for(uint8_t j=0; j<10; ++j){
 		mst_buf[0] = opcode;
 		mst_buf[1] = addr;
 		mst_buf[2] = value >> 8;
@@ -16,11 +16,22 @@ uint16_t spi_master_transceive(uint8_t opcode, uint8_t addr, uint16_t value)
 		spi_mst_start_packet();
 		spi_mst_write_read(5,mst_buf);
 		spi_mst_end_packet();
-	} while(mst_buf[1] != opcode || mst_buf[2] != addr); // wait for echoed opcode
-	//TODO: validate opcode and addr
-
-	// bytes from slave are received shifted right by one
-	return ((mst_buf[3] << 8) | mst_buf[4]);
+		for(uint8_t i=0; i<5; ++i){
+			mst_buf[0] = 0;
+			mst_buf[1] = 0;
+			mst_buf[2] = 0;
+			mst_buf[3] = 0;
+			mst_buf[4] = 0;
+			spi_mst_start_packet();
+			spi_mst_write_read(5,mst_buf);
+			spi_mst_end_packet();
+			// bytes from slave are received shifted right by one
+			if(mst_buf[1] == opcode && mst_buf[2] == addr){ // valid answer
+				return ((mst_buf[3] << 8) | mst_buf[4]);
+			}
+		}
+//	}
+	return 0xffff; // error-code
 }
 
 

firmware/slavechip/main.c

@@ -1,11 +1,11 @@
 #include "main.h"
 #include "spi.h"
 
-uint16_t foo;
-uint8_t bar;
+uint8_t foo;
+uint16_t bar;
 
 void baz() {
-  
+  foo++;
 }
 
 
@@ -30,8 +30,8 @@ void softinit() {
 int __attribute__((noreturn)) main(void) {
   hardinit();
   softinit();
-  foo= 0xfafa;
-  bar = 0x87;
+  foo = 0x87;
+  bar= 0xfafa;
 
   for(;;){
     

firmware/slavechip/main.h

@@ -13,8 +13,8 @@
 #define SOFTTIMERNUMS 4
 #include "softtimer.h"
 
-extern uint16_t foo;
-extern uint8_t bar;
+extern uint8_t foo;
+extern uint16_t bar;
 
 void baz();
 

firmware/slavechip/spi_pointers.c

@@ -2,7 +2,7 @@
 #include "spi_pointers.h"
 #include "main.h"
 
-uint16_t *spi_proto_globals8[] = {
+uint8_t *spi_proto_globals8[] = {
                                   &foo,
                                   &foo,
                                   &foo,
@@ -11,7 +11,7 @@ uint16_t *spi_proto_globals8[] = {
                                   &foo,
                                   &foo
                                  };
-uint8_t *spi_proto_globals16[] = {
+uint16_t *spi_proto_globals16[] = {
                                   &bar,
                                   &bar,
                                   &bar,

firmware/slavechip/spi_pointers.h

@@ -5,8 +5,8 @@
 
 typedef void(*funptr_t)();
 
-extern uint16_t *spi_proto_globals8[];
-extern uint8_t *spi_proto_globals16[];
+extern uint8_t *spi_proto_globals8[];
+extern uint16_t *spi_proto_globals16[];
 extern funptr_t spi_proto_funcs[];