Does the Intel 430TX PCIset support single and double cycle deselect SRAMs?
Yes, both the Intel 430HX and Intel 430TX PCIsets are capable of handling both single cycle and double cycle deselect SRAMs. In a single-bank solution, it doesn’t matter which type you have in the system since there is never a deselecting of one bank to switch to another. As a result, 3-1-1-1,1-1-1-1 timings are possible with both types. In a dual bank configuration, where 256KB banks are toggled via the A18 pin, it is possible to cross the bank boundary on an L1 cache line fill. If this occurs, then A18 toggles and the first bank is deselected while the second bank is selected. If the banks consist of single cycle deselect SRAM, then a wait state MUST be inserted before the latching of the second burst address (toggling A18) causing 3-1-1-1,2-1-1-1 timings. This is handled internally by the north bridge when bits 5:4 in the Cache Control register are both set to ‘1’ to indicate dual cache configuration. If double cycle deselect SRAMs are implemented in a dual bank configuration, then
