GT-96100A Advanced Communication Controller
122
Revision 1.0
5.7.10
Ready* Support
The Ready* pin is sampled on three occasions:
One clock before the data is sampled to the GT-96100A.
On the last rising edge of the WrActive (see below) phase during a write cycle.
During all other phases Ready* is not sampled by the GT-96100A.
If Ready* is not asserted during the WrActive, AccToFirst, or AccToNext phases. These phases are extended
until Ready* is asserted again. The transaction may be indefinitely held off until Ready* is asserted.
NOTE: There are no SDRAM refreshes as long as an access to a device is not completed. Use Ready* carefully
on device accesses so it not interfere with the SDRAM refresh.
Figure 22: Ready* Extending AccToFirst on Read Cycle
TClk
ALE
AcctoFirst set to 5
CS*1
CSTiming*
DevRW*
Notes:
1. CS* is driven off the same rising TClk* as ALE. Throughout consecutive transactions to the same device, CS* will remain
asserted. This is why CS* must ALWAYS be qualified with CSTiming*.
2. Ready* is sampled as deasserted one clock before data should be sampled according to AcctoFirst. AD[63:0] is NOT
sampled by the GT-64120 on the following rising TClk.
3. Ready* is asserted on some following rising TClk.
4. AD[63:0] (DATA 1) is sampled on the following rising TClk of the rising TClk that Ready* was asserted. Effectively,
AccToFirst is 7 in this example (instead of the programmed 5).
4
Ready*
2
3
ADDRESS
AD[63:0]
DATA 1 DRIVEN FROM DEVICE
1. CS* is driven off the same rising TClk* as ALE. Throughout consecutive transactions to the same device, CS* will remain asserted. This is why CS* must
always be qualified with CSTiming*.
2. Ready* is sampled as deasserted one clock before data should be sampled according to AccToFirst. AD[63:0] is not sampled by GT–96100A on the following
rising TClk.
3. Ready* is asserted on some following rising TClk.
4. AD[63:0] (Data1) is sampled on the following rising TClk of the rising TClk that Ready* was asserted. Effectively, AccToFirst is 7 in this example (instead of
programmed 5).