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
Table 19 provides the DC electrical characteristics for the DUART interface of the MPC8540.
Table 19. DUART DC Electrical Characteristics
Parameter
Symbol
Min
Max
Unit
High-level input voltage
Low-level input voltage
VIH
VIL
IIN
2
OVDD + 0.3
V
V
–0.3
—
0.8
5
Input current
(VIN 1 = 0 V or VIN = VDD)
μA
High-level output voltage
VOH
OVDD – 0.2
—
—
V
V
(OVDD = min, IOH = –100 μA)
Low-level output voltage
VOL
0.2
(OVDD = min, IOL = 100 μA)
Note:
1.Note that the symbol VIN, in this case, represents the OVIN symbol referenced in Table 1
and Table 2.
7.2 DUART AC Electrical Specifications
Table 20 provides the AC timing parameters for the DUART interface of the MPC8540.
Table 20. DUART AC Timing Specifications
Parameter
Value
Unit
Notes
Minimum baud rate
Maximum baud rate
Oversample rate
Notes:
fCCB_CLK / 1048576
fCCB_CLK / 16
16
baud
baud
—
3
1, 3
2, 3
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 8th sampled 0 after the 1-to-0 transition of the start bit. Subsequent bit
values are sampled each 16th sample.
3.Guaranteed by design.
MPC8540 Integrated Processor Hardware Specifications, Rev. 4
Freescale Semiconductor
21
FREESCALE [ Freescale ]
