Tews Technologies TPMC118-SW-95, Руководство пользователя

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TPMC118-SW-95 – QNX6 Neutrino Device Driver Page 27 of 30
3.3.9 DCMD_TP118_SYNCREAD
NAME
DCMD_TP118_SYNCREAD – Read all synchronized encoder channels
DESCRIPTION
This devctl function reads all synchronized encoder channels. A pointer to the callers message buffer
(
TP118_SYNCREAD ) and the size of this structure is passed by the parameters data_ptr and n_bytes
to the device.
The TP118_SYNCREAD structure has the following layout:
typedef struct
{
long value[TP118_MAX_CHANS];
unsigned char valid[TP118_MAX_CHANS];
} TP118_SYNCREAD, *PTP118_SYNCREAD;
value[]
This array returns the encoder values of the synchronized channels, all channels that are not
set to synchronized mode will be returned as 0. The array index specifies the assigned channel.
Index 0 specifies channel 1, index 1 specifies channel 2 and so on.
valid[]
This array returns flags for each channel if it is set to synchronous mode or not. If value is set to
TRUE , the channel is synchronized and the value is valid. If FALSE is returned, the channel is
not synchronized and 0 will be returned for this channel. The array index specifies the assigned
channel. Index 0 specifies channel 1, index 1 specifies channel 2 and so on.