i.MX25 Applications Processor for Consumer and Industrial Products, Rev. 10
Freescale Semiconductor
43
3.7.2
ATA Timing Parameters
Table 35 shows parameters used to specify the ATA timing. These parameters depend on the
implementation of the ATA interface on silicon, the bus buffer used, the cable delay and cable skew.
Table 35. Timing Parameters
Name
Description
Value/Contributing Factor
T
Bus clock period
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
7ns
5ns
4ns
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
Maximum difference in propagation delay bus clock L-to-H to any of the
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
Maximum difference in buffer propagation delay for any of the 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
Maximum difference in buffer propagation delay for any of the following signals
ata_iordy, ata_data (read)
Transceiver
tbuf
Maximum 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
Maximum difference in cable propagation delay between ata_iordy and
ata_data (read)
Cable
tskew5
Maximum difference in cable propagation delay between (ata_dior, ata_diow,
ata_dmack) and ata_cs0, ata_cs1, ata_da2, ata_da1, ata_da0,
ata_data(write)
Cable
tskew6
Maximum difference in cable propagation delay without accounting for ground
bounce
Cable