MCIMX515CJM6C Freescale, MCIMX515CJM6C Datasheet - Page 115

• Manufacturer Part Number: MCIMX515CJM6C
• Manufacturer: Freescale

Specifications of MCIMX515CJM6C

• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

Table 90
transfer modes.
The user needs to use level shifters for 5.0 V compatibility on the ATA interface. The i.MX51 P-ATA
interface is 3.3 V compatible.
The use of bus buffers introduces delay on the bus and introduces skew between signal lines. These factors
make it difficult to operate the bus at the highest speed (UDMA-4) when bus buffers are used. If fast
UDMA mode operation is needed, this may not be compatible with bus buffers.
Another area of attention is the slew rate limit imposed by the ATA specification on the ATA bus.
According to this limit, any signal driven on the bus should have a slew rate between 0.4 and 1.2 V/ns with
a 40 pF load. Not many vendors of bus buffers specify slew rate of the outgoing signals.
When bus buffers are used, the ata_data bus buffer is special. This is a bidirectional bus buffer, so a
direction control signal is needed. This direction control signal is ata_buffer_en. When its high, the bus
should drive from host to device. When its low, the bus should drive from device to host. Steering of the
signal is such that contention on the host and device tri-state busses is always avoided.
In the timing equations, some timing parameters are used. These parameters depend on the implementation
of the i.MX51 P-ATA interface on silicon, the bus buffer used, the cable delay and cable skew.
Freescale Semiconductor
1
SRISE and SFALL shall meet this requirement when measured at the sender’s connector from 10–90% of full signal
amplitude with all capacitive loads from 15
SI1
SI2
SI3
ID
ATA Interface Signals
and
Rising edge slew rate for any signal on ATA interface.
Falling edge slew rate for any signal on ATA interface (see note)
Host interface signal capacitance at the host connector
Figure 72
i.MX51 Applications Processors for Consumer and Industrial Products, Rev. 4
define the AC characteristics of all the P-ATA interface signals on all data
Table 90. AC Characteristics of All Interface Signals
Figure 72. P-ATA Interface Signals Timing Diagram
Parameter
–
40 pF where all signals have the same capacitive load value.
SI2
1
SI1
Symbol
C
S
S
host
rise
fall
Min
—
—
—
Electrical Characteristics
Max
1.25
1.25
20
Unit
V/ns
V/ns
pF
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