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MAX5945
Use the program registers (Table 29) to set the nominal
value for tFAULT and tSTART for all ports according to
the following formula:
tFAULT nominal = 40.96ms + 2.72ms x N
tSTART nominal = 40.96ms + 2.72ms x N
where N is the decimal value of TF_PR[3:0] or
TS_PR[3:0], respectively.
A reset sets R28h = 77h, which sets tFAULT = tSTART =
60ms as shown in the Electrical Characteristics. Use
R28h in conjunction with the two TSTART and TFAULT
bits in register R16h to program the values of tFAULT
and tSTART from about 20ms to almost 330ms with a
2.72ms resolution.
Example: Set TF_PR[3:0] = 1111b, TFAULT[1:0] = 11b
Then:
tFAULT = 4 x tFAULT nominal
= 4 x (40.96ms + 2.72ms x 15)
= 327ms
Note: The programmed value has the same percent-
age tolerance as the value specified in the Electrical
Characteristics.
Quad Network Power Controller
for Power-Over-LAN
34
______________________________________________________________________________________
ADDRESS = 28h
SYMBOL
BIT
R/W
DESCRIPTION
7
R
TF_PR[3]. tFAULT nominal programming bit 3.
6
R
TF_PR[2]. tFAULT nominal programming bit 2.
5
R
TF_PR[1]. tFAULT nominal programming bit 1.
TF_PR
4
R
TF_PR[0]. tFAULT nominal programming bit 0.
3
R
TS_PR[3]. tSTART nominal programming bit 3.
2
R
TS_PR[2]. tSTART nominal programming bit 2.
1
R
TS_PR[1]. tSTART nominal programming bit 1.
TS_PR
0
R
TS_PR[0]. tSTART nominal programming bit 0.
Table 29. Program Register 3