PNI TCM - Manual (Page 63)

PNI Sensor Corporation DOC#1014688 r06
TCM User Manual – July 2013 Page 58
Example: With a baud rate of 38400, the minimum delay after sending FF
h
is:
Minimum delay at 38400 baud = 7E-4 – (10/38400) = 4.4E-4 seconds = 440 µs
Sync Mode generally is intended for applications in which sampling does not occur
frequently. For applications where Sync Mode sampling will be at a frequency of 1 Hz
or higher, there is a minimum allowable delay between taking samples. This minimum
delay between samples (approximately inverse to the maximum sample rate) varies from
100 msec to 1.06 second and is a function of the number of FIR filter taps, as defined by
the following formula:
Minimum Delay between Samples (in seconds) = 0.1 + 0.03*(number of Taps)
7.3.35 kSetSyncModeResp (frame ID 47
d
)
This frame is the response to kSetSyncMode frame. The payload contains the Mode ID
requested.
Mode ID
UInt8
Payload
7.3.36 kSyncRead (frame ID 49
d
)
If the TCM is configured to operate in Sync Mode, as defined by kSetSyncMode, then
this frame wakes up the module, requests a measurement, outputs the results, then powers
down again. This frame has no payload. The response is kGetDataResp, with heading,
pitch, and roll automatically set as the data component IDs.
Prior to sending the kSyncRead frame, the user’s system must first send an “FF
h
” string
which wakes up the system, then wait some minimum delay time before sending the
kSyncRead frame. The minimum delay time is dependent on the baud rate, and for a
baud rate equal to or slower than 9600 there is no delay. The minimum delay is defined
by the same formula given for switching from Sync Mode to Normal Mode in
kSetSyncMode.