Rainbow Electronics MAX5945 - Manual (Page 33)

Use TF_PR[3:0] to set the nominal value for t DISC
according to the following formula:
t DISC nominal = 238ms + 16ms x N
where N is the decimal value of the binary words
TF_PR[3:0].
A reset sets R27h = 47h, which sets t DISC nominal =
350ms as shown in the Electrical Characteristics. Use
R27h in conjunction with the two TDISC[1:0] bits in reg-
ister R16h to program the values of t
DISC
from 60ms to
almost 340ms with a 16ms resolution.
Example: Set TD_PR[3:0] = 1111b, TDISC[1:0] = 11b
Then:
t DISC = 2 x t DISC nominal
= 2 x (238ms + 16ms x 15)
= 956ms
Note: The programmed value has the same percent-
age tolerance as the value specified in the Electrical
Characteristics.
MAX5945
Quad Network Power Controller
for Power-Over-LAN
______________________________________________________________________________________ 33
ADDRESS = 23h
SYMBOL BIT R/W
DESCRIPTION
7 R/W IGATE[2]
6 R/W IGATE[1] IGATE
5 R/W IGATE[0]
DET_BYP 4 R/W Detect bypass protection in AUTO mode
OSCF_RS 3 R/W OSC_FAIL Reset Bit
2 R/W AC_TH[2]
1 R/W AC_TH[1] AC_TH
0 R/W AC_TH[0]
Table 27. Program Register 1
ADDRESS = 27h
SYMBOL BIT R/W
DESCRIPTION
7 R IMAX[3]. V SU_LIM programming bit 3.
6 R IMAX[2]. V SU_LIM programming bit 2.
5 R IMAX[1]. V SU_LIM programming bit 1.
IMAX
4 R IMAX[0]. V SU_LIM programming bit 0.
3 R TD_PR[3]. t DISC nominal programming bit 3.
2 R TD_PR [2]. t DISC nominal programming bit 2.
1 R TD_PR [1]. t DISC nominal programming bit 1.
TD_PR
0 R TD_PR [0]. t DISC nominal programming bit 0.
Table 28. Program Register 2