MCIMX31LITEKITC Freescale Semiconductor, MCIMX31LITEKITC Datasheet - Page 27

• Manufacturer Part Number: MCIMX31LITEKITC
• Description: BOARD DEV FOR I.MX31
• Manufacturer: Freescale Semiconductor
• Type: MCUr

Specifications of MCIMX31LITEKITC

• Contents: Module and Misc Hardware
• For Use With/related Products: i.MX31
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.3.5
This section discusses ATA parameters. For a detailed description, refer to the ATA specification.
The user needs to use level shifters for 3.3 Volt or 5.0 Volt compatibility on the ATA interface.
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-5) 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.
Freescale Semiconductor
OW7
OW8
OW9
ID
ATA Electrical Specifications (ATA Bus, Bus Buffers)
1-Wire bus
(BATT_LINE)
1-Wire bus
(BATT_LINE)
Write 1 / Read Low Time
Transmission Time Slot
Release Time
Parameter
Figure 9. Write 1 Sequence Timing Diagram
Figure 10. Read Sequence Timing Diagram
MCIMX31/MCIMX31L Technical Data, Rev. 4.1
Table 23. WR1/RD Timing Parameters
OW7
OW7
OW9
t
Symbol
RELEASE
t
t
LOW1
SLOT
OW8
OW8
Min
60
15
1
Typ
117
—
5
Electrical Characteristics
Max
120
15
45
Units
µs
µs
µs
27