DUART
7 DUART
This section describes the DC and AC electrical specifications for the DUART interface of the MPC8540.
7.1 DUART DC Electrical Characteristics
provides the DC electrical characteristics for the DUART interface of the MPC8540.
Table 19. DUART DC Electrical Characteristics
Parameter
High-level input voltage
Low-level input voltage
Input current
(V
IN 1
= 0 V or V
IN
= V
DD)
High-level output voltage
(OV
DD
= min, I
OH
= –100
μA)
Low-level output voltage
(OV
DD
= min, I
OL
= 100
μA)
Symbol
V
IH
V
IL
I
IN
V
OH
V
OL
Min
2
–0.3
—
Max
OV
DD
+ 0.3
0.8
±5
Unit
V
V
μA
OV
DD
– 0.2
—
—
V
0.2
V
Note:
1.Note that the symbol V
IN
, in this case, represents the OV
IN
symbol referenced in
and
7.2 DUART AC Electrical Specifications
provides the AC timing parameters for the DUART interface of the MPC8540.
Table 20. DUART AC Timing Specifications
Parameter
Minimum baud rate
Maximum baud rate
Oversample rate
Value
f
CCB_CLK
/ 1048576
f
CCB_CLK
/ 16
16
Unit
baud
baud
—
Notes
3
1, 3
2, 3
Notes:
1.Actual attainable baud rate will be limited by the latency of interrupt processing.
2.The middle of a start bit is detected as the 8
th
sampled 0 after the 1-to-0 transition of the start bit. Subsequent bit
values are sampled each 16
th
sample.
3.Guaranteed by design.
MPC8540 Integrated Processor Hardware Specifications, Rev. 4
Freescale Semiconductor
21
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
