AS and JTAG access to cyclone II device

Combination of AS and JTAG configuration schemes is described under "Combining JTAG & Active Serial Configuration Schemes". Basically it's an AS configuration circuit with additional JTAG header. No switch or similar element is required for it, because JTAG takes precedence over AS, you should however observe the comments about disabling configuration with a blank device.

For newer devices, e.g. Cyclone III, the a circuit for the combined scheme is shown in the device handbook.

It should be noted, that the AS flash can be also written through JTAG indirect programming for all Cyclone family FPGAs series, so the AS header isn't strictly required.