Technical data

MCIMX31C/MCIMX31LC Technical Data, Rev. 4.3
22 Freescale Semiconductor
Electrical Characteristics
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.
4.3.5.1 Timing Parameters
In the timing equations, some timing parameters are used. These parameters depend on the implementation
of the ATA interface on silicon, the bus buffer used, the cable delay and cable skew. Table 21 shows ATA
timing parameters.
Table 21. ATA Timing Parameters
Name Description
Value/
Contributing Factor
1
T Bus clock period (ipg_clk_ata) peripheral clock
frequency
ti_ds Set-up time ata_data to ata_iordy edge (UDMA-in only)
UDMA0
UDMA1
UDMA2, UDMA3
UDMA4
UDMA5
15 ns
10 ns
7 ns
5 ns
4 ns
ti_dh Hold time ata_iordy edge to ata_data (UDMA-in only)
UDMA0, UDMA1, UDMA2, UDMA3, UDMA4
UDMA5
5.0 ns
4.6 ns
tco Propagation delay bus clock L-to-H to
ata_cs0, ata_cs1, ata_da2, ata_da1, ata_da0, ata_dior, ata_diow, ata_dmack, ata_data,
ata_buffer_en
12.0 ns
tsu Set-up time ata_data
to bus clock L-to-H 8.5 ns
tsui Set-up time ata_iordy to bus clock H-to-L 8.5 ns
thi Hold time ata_iordy
to bus clock H to L 2.5 ns
tskew1 Max difference in propagation delay bus clock L-to-H to any of following signals
ata_cs0, ata_cs1, ata_da2, ata_da1, ata_da0, ata_dior, ata_diow, ata_dmack, ata_data
(write), ata_buffer_en
7ns
tskew2 Max difference in buffer propagation delay for any of following signals
ata_cs0, ata_cs1, ata_da2, ata_da1, ata_da0, ata_dior, ata_diow, ata_dmack, ata_data
(write), ata_buffer_en
transceiver
tskew3 Max difference in buffer propagation delay for any of following signals ata_iordy, ata_data
(read)
transceiver
tbuf Max buffer propagation delay transceiver
tcable1 Cable propagation delay for ata_data cable
tcable2 Cable propagation delay for control signals ata_dior, ata_diow, ata_iordy, ata_dmack cable
tskew4 Max difference in cable propagation delay between ata_iordy and ata_data (read) cable