custom peripheral

Hi everyone,

Has anyone of you tried to develop custom peripherals for SOPC Builder???? If so can you just suggest me in addition to the source file(VHDL) how should i specify the register file and avalon bus specification file. Can you also send me some links where i can get some material on it???? If anyone of you has tried adding the PWM component can u just send that as an attachment????

Bye

Rakesh