Is there a way to program an epcs prom in circuit without using Nios?

Hello,

basically you can access SFL from an embedded processor, but you have to understand the virtual JTAG programming interface in FPGA. Alt_pfl and underlying sld_virtual_jtag Megafunction sources supplied with Qurtus give you some support, also the respective Megafunction user guides.

Some aspects of VJ are yet undocumented, but understandable to my opinion. I think however, that in-system programming through an embedded processor could better be achieved by accessing the AS interface directly, you just need a few tristate drivers, could be also tristatable PIO pins. As an advantage, this technique doesn't depend on previous succesful configuration of FPGA, thus could be used for initial programming in production and can recover in case of faulty configuration.

Regards,

Frank