Requires firmware V1.1 or higher. This function writes to the asynch registers and sets the direction of the D lines (input/output) as needed.
Execution time for this function is 60 milliseconds or less (typically 48 milliseconds in Windows).
The actual 1-bit time is about 1.833 plus a “full” delay (µs).
The actual 1/2-bit time is about 1.0 plus a “half” delay (µs). full/half delay = 0.833 + 0.833C + 0.667BC + 0.5ABC (µs)
Table 4.12-1. Common baud rates
|
Rate |
Full A,B,C |
Half A,B,C |
|
1 |
55,153,232 |
114,255,34 |
|
10 |
63,111,28 |
34,123,23 |
|
100 |
51,191,2 |
33,97,3 |
|
300 |
71,23,4 |
84,39,1 |
|
600 |
183,3,6 |
236,7,1 |
|
1000 |
33,29,2 |
123,8,1 |
|
1200 |
23,17,4 |
14,54,1 |
|
2400 |
21,37,1 |
44,3,3 |
|
4800 |
10,18,2 |
1,87,1 |
|
7200 |
134,2,1 |
6,9,2 |
|
9600 |
200,1,1 |
48,2,1 |
|
10000 |
63,3,1 |
46,2,1 |
|
19200 |
96,1,1 |
22,2,1 |
|
38400 |
3,5,2 |
9,2,1 |
|
57600 |
3,3,2 |
11,1,1 |
|
100000 |
3,3,1 |
1,2,1 |
|
115200 |
9,1,1 |
2,1,1 or 1,1,1 |
When using data rates over 38.4 kbps, the following conditions need to be considered:
-
When reading the first byte, the start bit is first tested about 11.5 µs after the start of the tx stop bit.
-
When reading bytes after the first, the start bit is first tested about “full” + 11 us after the previous bit 8 read, which occurs near the middle of bit 8.
When enabled, STB does the following to aid in debugging asynchronous reads:
-
STB is set about 6 µs after the start of the last tx stop bit, or about “full” + 6 us after the previous bit 8 read.
-
STB is cleared about 0-2 us after the RX start bit is detected.
-
STB is set after about “half”.
-
STB is cleared after about “full”.
-
Bit 0 is read about 1 µs later.
-
STB is set about 1 µs after the bit 0 read.
-
STB is cleared after about “full”.
-
Bit 1 is read about 1 µs later.
-
STB is set about 1 µs after the bit 1 read.
-
STB is cleared after about “full”.
-
This continues for all 8 data bits and the stop bit, after which STB remains low.
Declaration:
long AsynchConfig ( long *idnum,
long demo,
long timeoutMult,
long configA,
long configB,
long configTE,
long fullA,
long fullB,
long fullC,
long halfA,
long halfB,
long halfC )
Outputs:
-
*idnum – Returns the local ID or –1 if no LabJack is found.