Configuration Handbook - Kamami.pl

Configuring APEX 20KE & APEX 20KC DevicesTable 7–9. Dedicated Configuration Pins on the APEX 20KE & APEX 20KC Device (Part 5 of 5)Pin NameUserModeConfigurationSchemePin TypeDescriptionRDYnBSY I/O PPS and PPA Output Ready output. A high output indicates that the targetdevice is ready to accept another data byte. A low outputindicates that the target device is busy and not ready toreceive another data byte.In PPS and PPA configuration schemes, this pin willdrive out high after power-up, before configuration andafter configuration before entering user-mode.In non-PPS and non-PPA schemes, it functions as a userI/O during configuration, which means it is tri-stated.After PPS and PPA configuration, RDYnBSY is availableas a user I/O and the state of this pin depends on theDual-Purpose Pin settings.nCS/CS I/O PPA Input Chip-select inputs. A low on nCS and a high on CS selectthe target device for configuration. The nCS and CS pinsmust be held active during configuration andinitialization.During the PPA configuration mode, it is only required touse either the nCS or CS pin. Therefore, if only one chipselectinput is used, the other must be tied to the activestate. For example, nCS can be tied to ground while CSis toggled to control configuration.In non-PPA schemes, it functions as a user I/O duringconfiguration, which means it is tri-stated.After PPA configuration, nCS and CS are available as auser I/O pins and the state of these pins depends on thedual-purpose pin settings.Altera Corporation 7–63August 2005 Configuration Handbook, Volume 1