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1 files changed, 14 insertions, 7 deletions

diff --git a/mycan.c b/mycan.c
index 0a6c106..56add73 100644
--- a/mycan.c
+++ b/mycan.c
@@ -45,6 +45,7 @@ cansend vcan0 680#00.FF.02.00.02.00.02.00
 // 10+96*7+96*4+1=1067 bytes
 #define ENTRY_SIZE 1067
 
+// Convert can message to uint64_t
 // https://github.com/howerj/dbcc MIT
 static uint64_t u64_from_can_msg(const uint8_t m[8]) {
 	return ((uint64_t)m[7] << 56) | ((uint64_t)m[6] << 48) | ((uint64_t)m[5] << 40) | ((uint64_t)m[4] << 32) 
@@ -59,6 +60,7 @@ int main(int argc, char **argv)
 	struct ifreq ifr;
 	struct can_frame frame;
 	char *filename;
+	// Initialize filename to $XDG_DATA_HOME/mycan.csv. If no XDG_DATA_HOME environment variable, then initialize to $HOME/.local/share/mycan.csv
 	{
 		// usually ~/.local/share
 		const char *dir=getenv("XDG_DATA_HOME");
@@ -81,12 +83,11 @@ int main(int argc, char **argv)
 
 	memset(&frame, 0, sizeof(struct can_frame));
 
+	// No need any more because I use systemd unit to autostart configure CAN network interface
 	//system("sudo ip link set can0 type can bitrate 500000");
 	//system("sudo ifconfig can0 up");
-	// vcan, for test
-	//printf("this is a can receive demo\r\n");
 
-	// check and fix corrupted .csv file
+	// Check and fix corrupted .csv file due to power failure.
 	for(FILE *fp;(fp=fopen(filename,"r"))!=NULL;)
 	{
 		char ch;
@@ -120,6 +121,9 @@ int main(int argc, char **argv)
 	// https://unix.stackexchange.com/questions/785686#comment1505589_785686
 	fflush(stdout);
 
+	// https://www.waveshare.com/wiki/RS485_CAN_HAT
+	// Using Linux kernel's SocketCAN
+	// https://docs.kernel.org/networking/can.html
 	//1.Create socket
 	s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 	if (s < 0) {
@@ -148,7 +152,8 @@ int main(int argc, char **argv)
 	}
 
 	//4.Define receive rules
-	// 24 (voltage) + 16 (temp)
+	// Adding masks to the socket, to only read CAN ids I want.
+	// 24 (voltage) + 16 (temp) can ids
 	struct can_filter rfilter[CAN_VOLT_LEN+CAN_TEMP_LEN];
 	rfilter[0].can_id = 0x630;
 	rfilter[0].can_mask = CAN_SFF_MASK;
@@ -166,7 +171,7 @@ int main(int argc, char **argv)
 	}
 	setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter));
 
-	//5.Receive data and exit
+	//5.Receive data
 	for(t_before=time(NULL);;)
 	{
 		nbytes = read(s, &frame, sizeof(frame));
@@ -175,7 +180,6 @@ int main(int argc, char **argv)
 			uint8_t iout;
 			FILE * fp;
 
-			// try FIFO, socket and other file types maybe better, not sure
 			if((fp=fopen(filename,"a"))==NULL)
 			{
 				fprintf(stderr,"Can't open file \"%s\".\n",filename);
@@ -187,14 +191,17 @@ int main(int argc, char **argv)
 			//	printf("data[%d] = %d\r\n", i, frame.data[i]);
 			can_message_u64 = u64_from_can_msg(frame.data);
 			t=time(NULL);
+			// Unpack CAN message and save to obj. This function is automatically generated using dbcc.
 			unpack_message(&obj,frame.can_id,can_message_u64,frame.can_dlc,t);
 			//printf("my prints:\n");
 			//print_message(&obj, frame.can_id, stdout);
 			//printf("my timestamp: %u\n", t);
+
+			// Decode CAN message and write to file, using decode functions generated automatically using dbcc.
 			if(t>t_before)
 			{
 				t_before=t;
-				// Maybe better if concat strings and print all at once
+				// Maybe better if concat strings and print all at once, but it would be more complicated, I tried, see git log
 				fprintf(fp,"%u",t);
 				decode_can_0x630_BMS_M1_Cell_1_Voltage(&obj,&out);
 				fprintf(fp,",%6.4f",out);