VS23S040 Blanking Time?

Designing hardware and software that uses the VS23S0X0 family of ICs as a 8-bit or SPI SRAM memory or as a Video Controller for generating Composite Video (TV-Out) or driving other kinds of displays.
Post Reply
Ruprect
User
Posts: 1
Joined: Sat 2024-09-14 7:55

VS23S040 Blanking Time?

Post by Ruprect »

I am trying to feed composite video from the VS23040 into a wireless video sender device that seems very fussy about the timings it recieves.
Having looked at the video signals on a scope between various AV devices the sender will happily send, the major standout is the blanking period of the chip.

Software reads

// NTSC long sync duration is 27.3 us
#define LONG_SYNC_US 27.33275

Playing around with this setting seems to achieve very little. Is this set in stone?

NTSC standards call for blanking of 10.9 us.

Has anyone had any success reducing the blanking time?
Hannu
VLSI Staff
Posts: 546
Joined: Mon 2016-05-30 11:54
Location: Finland
Contact:

Re: VS23S040 Blanking Time?

Post by Hannu »

Hello,

Let's start by getting to same playing field.
Which software you are using? And what chip and hardware? And your video clock is correct NTSC crystal?

Can you dump the registers from VS23S010? I could try to walk back from that data, and try to figure out what is going on.

I'm currently comparing some pal.h and ntsc.h files (not necessarily same which you have) and my VS232S skills can be little bit in rust, but this starts to look like an interesting Monday.
Post Reply