Spectracom TPRO-cPCI, User Manual, Page: 37 / 46

TPRO-cPCI/TSAT-cPCI Spectracom Corporation
Synchronizable Timecode Generator User Manual 5-7
Compute N as follows:
For negative offsets:
N = offset (range 0x0000 through 0x0999)
For positive offsets:
N = offset (range 0x1000 through 0x1999)
NOTE: Be careful when writing software to increment or decrement this value. Only BCD
values are acceptable. For example, 0x0019 and 0x0020 are valid, but 0x001A is not.
Invalid values are ignored.
5.9 Read Number of Satellites Tracked and Altitude
0 x 0070 (TSAT-PMC Only)
Write command 0x00000070 to tbreg_cmd[3] to determine how many GPS satellites are being
tracked, and the computed altitude (elevation). Altitude units are "meters above mean sea
level." An ASCII string is returned. This contains the number (quantity) of satellites being
tracked and the altitude.
Bits tbreg_response[0] Bits tbreg_response[1]
31:24 fourth character 31:24 eight character
23:16 third character 23:16 seventh character
15:08 second character 15:08 sixth character
07:00 first character 07:00 fifth character
Bits tbreg_response[2] Bits tbreg_response[3]
31:24 twelfth character 31:16 (unused)
23:16 eleventh character 15:00 0x0070
15:08 tenth character
07:00 ninth character
The response string is formatted as
AAAA.A,M,SS\0 where “AAAA.A” is the altitude and “SS”
is the number of satellites tracked. The fields are delimited by commas, may (or may not)
include leading zeroes, and could vary in length. Altitudes below mean sea level begin with "
– ".
The " – " can appear in any of the “A” fields. Therefore, the following combinations could result:
(–999.9), (0–99.9), (00–9.9), (000–.9), but altitudes above mean sea level do not begin with "+".
Some antennas may not support below-sea-level conditions.
For example, "235.0,07\0" means that the TSAT-PMC is tracking 7 satellites, and the computed
altitude is 235.0 meters above mean sea level. The resolution of the altitude field may exceed
the accuracy of the altitude computation. Empty fields may be present when the TSAT-PMC is
not tracking satellites (e.g., "\0").