#define DAQ_FIFO_DEPTH 100
err_t tcp_write_u32_string(struct tcp_pcb *pcb, unsigned char prefix, u32_t value)
{
/* Because 0 <= u32_t <= 4294967295, the value itself is at most 10 digits long. */
unsigned char buf[11]; /* enough room for prefix and value. */
err_t result;
u16_t len;
unsigned char *p = buf + sizeof buf;
/* Construct the value first, from right to left. */
do {
/* ASCII encoding: '0' = 48, '1' = 49, ..., '9' = 57. */
*(--p) = 48 + (value % 10u);
value /= 10;
} while (value);
/* Prepend the prefix, if any. */
if (prefix)
*(--p) = prefix;
/* Calculate the length of this part. */
len = buf + sizeof buf - p;
/* If the TCP buffer does not have enough free space, flush it. */
if (tcp_sndbuf(pcb) < len) {
result = tcp_output(pcb);
if (result != ERR_OK)
return result;
}
/* Append the buffer to the TCP send buffer.
We also assume the packet is not done yet. */
return tcp_write(pcb, p, len, TCP_WRITE_FLAG_COPY | TCP_WRITE_FLAG_MORE);
}
err_t send_list(struct tcp_pcb *pcb, const u32_t data[], u16_t len)
{
static const char newline[2] = { 13, 10 }; /* ASCII \r\n */
err_t result;
if (len > 0) {
u16_t i;
/* The first number has no prefix. */
result = tcp_write_u32_string(pcb, 0, data[0]);
if (result != ERR_OK)
return result;
/* The following numbers have a comma prefix. */
for (i = 1; i < len; i++) {
/* ASCII comma is code 44. (Use 32 for space, or 9 for tab.) */
result = tcp_write_u32_string(pcb, 44, data[i]);
if (result != ERR_OK)
return result;
}
}
/* We add a final newline.
Note that this one can be referenced,
and it does complete what we wanted to send thus far. */
result = tcp_write(pcb, newline, 2, 0);
if (result)
return result;
/* and flush the buffer, so the packet gets sent right now. */
return tcp_output(pcb);
}
err_t application_connection(void *arg, struct tcp_pcb *conn, err_t err)
{
struct netif *echo_netif = arg; /* Because of tcp_arg(, netif). */
u32_t data[DAQ_FIFO_DEPTH];
u32_t i, n;
/* Drop the connection if there was an error. */
if (err != ERR_OK) {
tcp_abort(conn);
return ERR_ABRT;
}
/* Setup the data aquisition. */
err = daq_setup();
if (err != ERR_OK) {
tcp_abort(conn);
return ERR_ABRT;
}
/* Data acquisition to TCP loop. */
while (1) {
/* Keep the networking stack running. */
xemacif_input(echo_netif);
tcp_tmr();
/* Tell the networking stack to output what it can. */
tcp_output(conn);
/* Acquire up to DAQ_FIFO_DEPTH samples. */
n = daq_acquire(data, DAQ_FIFO_DEPTH);
if (n > DAQ_FIFO_DEPTH)
break;
/* Write data as-is to the tcp buffer. */
if (tcp_write(conn, data, n * sizeof data[0], TCP_WRITE_FLAG_COPY) != ERR_OK)
break;
}
/* Stop data acquisition. */
// daq_close();
/* Close the TCP connection. */
if (tcp_close(conn) == ERR_OK)
return ERR_OK;
/* Close failed. Abort it, then. */
tcp_abort(conn);
return ERR_ABRT;
}
int start_application()
{
struct tcp_pcb *pcb;
err_t err;
unsigned port = 7;
/* create new TCP PCB structure */
pcb = tcp_new();
if (!pcb) {
xil_printf("Error creating PCB. Out of Memory\n\r");
return -1;
}
/* bind to specified @port */
err = tcp_bind(pcb, IP_ADDR_ANY, port);
if (err != ERR_OK) {
xil_printf("Unable to bind to port %d: err = %d\n\r", port, err);
return -2;
}
/* we do not need any arguments to callback functions */
tcp_arg(pcb, NULL);
/* listen for connections */
pcb = tcp_listen(pcb);
if (!pcb) {
xil_printf("Out of memory while tcp_listen\n\r");
return -3;
}
/* specify callback to use for incoming connections */
tcp_accept(pcb, application_connection);
xil_printf("TCP echo server started @ port %d\n\r", port);
return 0;
}