FlapJackApps/libdivecomputer
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Automatically retry the command if the device does not respond.

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This commit is contained in:
Jef Driesen 2008-02-18 14:41:28 +00:00
parent f74e17068f
commit 52a9293e7d
1 changed files with 40 additions and 29 deletions
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69
suunto_d9.c
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@ -6,6 +6,8 @@
#include "serial.h"
#include "utils.h"
#define MAXRETRIES 2
#define MIN(a,b) (((a) < (b)) ? (a) : (b))
#define MAX(a,b) (((a) > (b)) ? (a) : (b))
@ -151,39 +153,48 @@ suunto_d9_transfer (d9 *device, const unsigned char command[], unsigned int csiz
{
assert (asize >= size + 4);
// Send the command to the dive computer.
int rc = suunto_d9_send (device, command, csize);
if (rc != SUUNTO_SUCCESS) {
WARNING ("Failed to send the command.");
return rc;
}
// Occasionally, the dive computer does not respond to a command.
// In that case we retry the command a number of times before
// returning an error. Usually the dive computer will respond
// again during one of the retries.
// Receive the answer of the dive computer.
rc = serial_read (device->port, answer, asize);
if (rc != asize) {
WARNING ("Failed to receive the answer.");
if (rc == -1)
return SUUNTO_ERROR_IO;
return SUUNTO_ERROR_TIMEOUT;
}
for (unsigned int i = 0;; ++i) {
// Send the command to the dive computer.
int rc = suunto_d9_send (device, command, csize);
if (rc != SUUNTO_SUCCESS) {
WARNING ("Failed to send the command.");
return rc;
}
// Verify the header of the package.
answer[2] -= size; // Adjust the package size for the comparision.
if (memcmp (command, answer, asize - size - 1) != 0) {
WARNING ("Unexpected answer start byte(s).");
return SUUNTO_ERROR_PROTOCOL;
}
answer[2] += size; // Restore the package size again.
// Receive the answer of the dive computer.
rc = serial_read (device->port, answer, asize);
if (rc != asize) {
WARNING ("Failed to receive the answer.");
if (rc == -1)
return SUUNTO_ERROR_IO;
if (i < MAXRETRIES)
continue; // Retry.
return SUUNTO_ERROR_TIMEOUT;
}
// Verify the checksum of the package.
unsigned char crc = answer[asize - 1];
unsigned char ccrc = suunto_d9_checksum (answer, asize - 1, 0x00);
if (crc != ccrc) {
WARNING ("Unexpected answer CRC.");
return SUUNTO_ERROR_PROTOCOL;
}
// Verify the header of the package.
answer[2] -= size; // Adjust the package size for the comparision.
if (memcmp (command, answer, asize - size - 1) != 0) {
WARNING ("Unexpected answer start byte(s).");
return SUUNTO_ERROR_PROTOCOL;
}
answer[2] += size; // Restore the package size again.
return SUUNTO_SUCCESS;
// Verify the checksum of the package.
unsigned char crc = answer[asize - 1];
unsigned char ccrc = suunto_d9_checksum (answer, asize - 1, 0x00);
if (crc != ccrc) {
WARNING ("Unexpected answer CRC.");
return SUUNTO_ERROR_PROTOCOL;
}
return SUUNTO_SUCCESS;
}
}