COM20020-5 Datasheet, PDF (52/58 Pages) SMSC Corporation – Universal Local Area Network Controller with 2K x 8 On-Board RAM

nTXEN
t4
nPULSE1
nPULSE2
t2
t1
t3
t1
t5
LAST BIT
(200 nS BIT TIME)
t2
RXIN
t6
t7
Parameter
t1
nPULSE1, nPULSE2 Pulse Width
t2
nPULSE1, nPULSE2 Period
t3
nPULSE1, nPULSE2 Overlap
t4
nTXEN Low to nPULSE1 Low**
t5
Beginning of Last Bit Time to nTXEN High**
t6
RXIN Pulse Width
t7
RXIN Period
min
typ max units
50 *
nS
200 *
nS
-10
0
+10 nS
400
500 nS
100
200 nS
10
50 *
nS
200 *
nS
* t1 = 2 x (crystal period) for clock frequencies other than 40 MHz.
* t2,t7 = 8 x (crystal period) for clock frequencies other than 40 MHz.
This period applies to data of two consecutive one's.
** t4: For clock frequencies other than 40 MHz, t4 = 18 x (crystal period) ± 50 nsec.
** t5: For clock frequencies other than 40 MHz, t5 = 6 x (crystal period) ± 50 nsec.
FIGURE 14 - NORMAL MODE TRANSMIT OR RECEIVE TIMING
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