Hello everyone! It is good to be back on the forums after taking a break.
I have added an external sram chip; 512Kx8 bit cmos sram,
product #: AS6C4008. I basically send out 16 bit address data to the sram from my PIC microcontroller and then the sram puts out vga pixel data.
I have a 64MHz clock but all instructions take 4 cycles due to pipe lining and so forth so I have instructions executing at 16Mhz. With that in mind I am sending address data to the sram at 16MHz. I have a Hsync of 31.5KHz so I should be getting about 16MHz/31.5KHz = 507 pixels per line. I have blanking periods included which take about 100 cycles so I basically change the address buffer 403 times exactly. This should mean that I get 403 pixels per line. In reality I have counted the number of pixel draws on my monitor and it comes out to 201 give or take 1 because I had to count them .
The sram seems to be giving the vga every other pixel. Why? Because I have put a marker pixel in the hline and it is where it should be but it is twice the width.
I appreciate any advice and no suggestion is a bad one, it is possible I am overlooking something simple. Thanks for the read.
I have added an external sram chip; 512Kx8 bit cmos sram,
product #: AS6C4008. I basically send out 16 bit address data to the sram from my PIC microcontroller and then the sram puts out vga pixel data.
I have a 64MHz clock but all instructions take 4 cycles due to pipe lining and so forth so I have instructions executing at 16Mhz. With that in mind I am sending address data to the sram at 16MHz. I have a Hsync of 31.5KHz so I should be getting about 16MHz/31.5KHz = 507 pixels per line. I have blanking periods included which take about 100 cycles so I basically change the address buffer 403 times exactly. This should mean that I get 403 pixels per line. In reality I have counted the number of pixel draws on my monitor and it comes out to 201 give or take 1 because I had to count them .
The sram seems to be giving the vga every other pixel. Why? Because I have put a marker pixel in the hline and it is where it should be but it is twice the width.
I appreciate any advice and no suggestion is a bad one, it is possible I am overlooking something simple. Thanks for the read.