LM3S808 Datasheet, PDF (388/416 Pages) List of Unclassifed Manufacturers – Microcontroller

Electrical Characteristics
19.2.5
19.2.6
I²C
Table 19-11. I²C Characteristics
Parameter No. Parameter Parameter Name
Min Nom Max
Unit
I1^a
t_SCH Start condition hold time
36 -
-
system clocks
I2^a
t_LP
Clock Low period
36 -
-
system clocks
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 19-2. I²C Timing
I2
I6
I5
I2CSCL
I1
I4
I7
I8 I3
I9
I2CSDA
Synchronous Serial Interface (SSI)
Table 19-12. SSI Characteristics
Parameter No. Parameter Parameter Name
Min Nom Max
Unit
S1
t_{clk_per} SSIClk cycle time
S2
t_{clk_high} SSIClk high time
S3
t_{clk_low} SSIClk low time
2 - 65024 system clocks
- 1/2 -
t clk_per
- 1/2 -
t clk_per
S4
t_clkrf SSIClk rise/fall time
- 7.4 26
ns
S5
t_DMd Data from master valid delay time 0 - 20
ns
S6
t_DMs Data from master setup time
20 -
-
ns
S7
t_DMh Data from master hold time
40 -
-
ns
S8
t_DSs Data from slave setup time
20 -
-
ns
S9
t_DSh Data from slave hold time
40 -
-
ns
388
October 01, 2007
Preliminary