LM3S6950 Datasheet, PDF (489/524 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S6950 Microcontroller
Parameter No. Parameter Parameter Name
Min Nom Max
Unit
I3^b
t_SRT I2CSCL/I2CSDA rise time (V_IL =0.5 V to V _IH =2.4 V) - - (see note b)
ns
I4^a
t_DH Data hold time
2-
-
system clocks
I5^c
t_SFT I2CSCL/I2CSDA fall time (V_IH =2.4 V to V _IL =0.5 V) - 9
10
ns
I6^a
t_HT Clock High time
24 -
-
system clocks
I7^a
t_DS Data setup time
18 -
-
system clocks
I8^a
t_SCSR Start condition setup time (for repeated start condition 36 -
-
system clocks
only)
I9^a
t_SCS Stop condition setup time
24 -
-
system clocks
a. Values depend on the value programmed into the TPR bit in the I²C Master Timer Period (I2CMTPR) register; a TPR
programmed for the maximum I2CSCL frequency (TPR=0x2) results in a minimum output timing as shown in the table
above. The I ²C interface is designed to scale the actual data transition time to move it to the middle of the I2CSCL Low
period. The actual position is affected by the value programmed into the TPR; however, the numbers given in the above
values are minimum values.
b. Because I2CSCL and I2CSDA are open-drain-type outputs, which the controller can only actively drive Low, the time
I2CSCL or I2CSDA takes to reach a high level depends on external signal capacitance and pull-up resistor values.
c. Specified at a nominal 50 pF load.
Figure 22-2. I²C Timing
I2
I6
I5
I2CSCL
I1
I4
I7
I8 I3
I9
I2CSDA
22.2.5
Ethernet Controller
Table 22-11. 100BASE-TX Transmitter Characteristics^a
Parameter Name
Min Nom Max Unit
Peak output amplitude
950 - 1050 mVpk
Output amplitude symmetry 0.98 - 1.02 mVpk
Output overshoot
-- 5%
Rise/Fall time
3 - 5 ns
Rise/Fall time imbalance
- - 500 ps
Duty cycle distortion
- - - ps
Jitter
- - 1.4 ns
a. Measured at the line side of the transformer.
Table 22-12. 100BASE-TX Transmitter Characteristics (informative)^a
Parameter Name
Min Nom Max Unit
Return loss
16 - - dB
Open-circuit inductance 350 - - µs
a. The specifications in this table are included for information only. They are mainly a function of the external transformer
and termination resistors used for measurements.
June 14, 2007
489
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