Hi all, Has anyone got some knowledge of CAS before RAS refresh? Does CAS go LOW, then RAS gets cycled for each ROM address, then CAS goes HIGH again? I have a 4 Meg X 9 30 pin SIMM hooked up to a 16F877 and while it appears to work, I don't know if the refresh is correct. -- Best regards Tony mICros http://www.bubblesoftonline.com mailto:sales@bubblesoftonline.com -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu