In MD-ASB configuration, FLEX 8000 devices are configured via a parallel configuration device and a supporting PLD. The configuration device must have a maximum access time of 100 ns. Each bit in the configuration device data word (up to 8 bits wide) configures a different FLEX 8000 device.
The nSTATUS pins of the FLEX 8000 devices are tied together and to the nRESET pin of the supporting PLD, such as a MAX® CPLD. This CPLD generates sequential addresses for the parallel configuration device. When nSTATUS pulses low, nRESET pulses low, making the support PLD reset its address counter. The low pulse on nSTATUS will drive the nSTATUS pin low on all other FLEX 8000 devices, restarting configuration.
For additional information on this topic, go to AN 33: Configuring FLEX 8000 devices (PDF) and AN 38: Configuring Multiple FLEX 8000 Devices (PDF).