crewID/libnfc
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Improved UART communication on POSIX systems:

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- Added "dynamic timeout" to "uart_send" function.
- Added "static timeout" to each iteration of the while loop (it seems to solve a lot of sync troubles during read operation). 
(Tested with PN532).
This commit is contained in:
Emanuele Bertoldi 2011-01-18 11:35:23 +00:00
parent 58c5662f35
commit eae07f1977
1 changed files with 10 additions and 4 deletions
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14
libnfc/buses/uart_posix.c
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@ -261,7 +261,8 @@ uart_receive (serial_port sp, byte_t * pbtRx, size_t * pszRx)
}
*pszRx += res;
tv.tv_usec = uiTimeoutPerByte * MIN( iExpectedByteCount, 16 ); // Reload timeout with a low value to prevent from waiting too long on slow devices (16x is enought to took at least 1 byte)
// Reload timeout with a low value to prevent from waiting too long on slow devices (16x is enought to took at least 1 byte)
tv.tv_usec = uiTimeoutStatic + uiTimeoutPerByte * MIN( iExpectedByteCount, 16 );
// DBG("Timeout reloaded at: %d µs", tv.tv_usec);
} while (byteCount && (iExpectedByteCount > 0));
@ -279,14 +280,16 @@ uart_send (serial_port sp, const byte_t * pbtTx, const size_t szTx)
int32_t res;
size_t szPos = 0;
fd_set rfds;
struct timeval tv;
const struct timeval tvDefault = { .tv_sec = 0, .tv_usec = 20000 };
struct timeval tvTimeout = {
.tv_sec = 0,
.tv_usec = uiTimeoutStatic + (uiTimeoutPerByte * szTx),
};
struct timeval tv = tvTimeout;
while (szPos < szTx) {
// Reset file descriptor
FD_ZERO (&rfds);
FD_SET (((serial_port_unix *) sp)->fd, &rfds);
tv = tvDefault;
res = select (((serial_port_unix *) sp)->fd + 1, NULL, &rfds, NULL, &tv);
// Write error
@ -308,6 +311,9 @@ uart_send (serial_port sp, const byte_t * pbtTx, const size_t szTx)
}
szPos += res;
// Reload timeout with a low value to prevent from waiting too long on slow devices (16x is enought to took at least 1 byte)
tv.tv_usec = uiTimeoutStatic + uiTimeoutPerByte * MIN( szTx - szPos, 16 );
}
return 0;
}