- Fri Apr 07, 2006 4:27 am
#11984
Hi to all
I am making a program that reads and writes to a ram (cypress) using the data ports (as i/o, bidirectional) and control ports (for the we, oe, etc) of the parallel port of my computer using visual basic, however when i tried the program at first i works fine, however after repeating entering and writing data to the ram i get a error, for example
Address Data input Data output
1 2 2
2 4 2
3 7 7
as you can see in the 2nd data output, the ram read the data on address 1 instead of 2! however this happens about 3/10 times so i know my program can write and read data correctly. but can anybody explain this? my ram has a 12ns access time so i thought timing should not be a problem, however eventhough i make the writing and reading equal to 1sec per instruction (we to high, address changes.. etc) i still get error messages. Btw, i connected the port directly to the ram without any resistors, becuase i that will only make a delay in the access time (correct?) thank you everyone
you can contact me at glenn.fetalvero@gmail.com
I am making a program that reads and writes to a ram (cypress) using the data ports (as i/o, bidirectional) and control ports (for the we, oe, etc) of the parallel port of my computer using visual basic, however when i tried the program at first i works fine, however after repeating entering and writing data to the ram i get a error, for example
Address Data input Data output
1 2 2
2 4 2
3 7 7
as you can see in the 2nd data output, the ram read the data on address 1 instead of 2! however this happens about 3/10 times so i know my program can write and read data correctly. but can anybody explain this? my ram has a 12ns access time so i thought timing should not be a problem, however eventhough i make the writing and reading equal to 1sec per instruction (we to high, address changes.. etc) i still get error messages. Btw, i connected the port directly to the ram without any resistors, becuase i that will only make a delay in the access time (correct?) thank you everyone
you can contact me at glenn.fetalvero@gmail.com