Ds1874 sfp+ controller with digital ldd interface – Rainbow Electronics DS1874 User Manual
Page 69
DS1874
SFP+ Controller with Digital LDD Interface
______________________________________________________________________________________
69
Table 02h, Register BDh: LTXP
FACTORY
DEFAULT
00h
READ ACCESS
PW2 or (PW1 and RWTBL246) or (PW1 and RTBL246)
WRITE ACCESS
PW2 or (PW1 and RWTBL246)
MEMORY
TYPE Nonvolatile
(SEE)
BDh 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
BIT
7
BIT
0
Fast-comparison DAC threshold adjust for low TXP. This value is subtracted from the APC DAC value recalled
from Table 04h. If the difference is less than 0x00, 0x00 is used. Comparisons less than V
LTXP
, compared
against V
MON2
, create a TXP LO alarm. The same ranging applied to the APC DAC should be used here.
V
LTXP
=
Full Scale
255
APC DAC LTXP
(
)
FACTORY
DEFAULT
00h
READ ACCESS
PW2 or (PW1 and RWTBL246) or (PW1 and RTBL246)
WRITE ACCESS
PW2 or (PW1 and RWTBL246)
MEMORY TYPE
Nonvolatile (SEE)
BEh 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
BIT
7
BIT
0
Fast-comparison DAC threshold adjust for high LOS. The combination of HLOS and LLOS creates a hysteresis
comparator. As RSSI falls below the LLOS threshold, the LOS LO alarm bit is set to 1. The LOS alarm remains set
until the RSSI input is found above the HLOS threshold setting, which clears the LOS LO alarm bit and sets the
LOS HI alarm bit. At power-on, both LOS LO and LOS HI alarm bits are 0 and the hysteresis comparator uses the
LLOS threshold setting.
V
HLOS
=
Full Scale
255
HLOS
FACTORY
DEFAULT
00h
READ ACCESS
PW2 or (PW1 and RWTBL246) or (PW1 and RTBL246)
WRITE ACCESS
PW2 or (PW1 and RWTBL246)
MEMORY TYPE
Nonvolatile (SEE)
BFh 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
BIT
7
BIT
0
Fast-comparison DAC threshold adjust for low LOS. See HLOS (Table 02h, Register BEh) for functional description.
V
LLOS
=
Full Scale
255
LLOS
Table 02h, Register BEh: HLOS
Table 02h, Register BFh: LLOS