- Fri Jan 30, 2009 9:57 pm
#64965
Lightyear,
I'm glad you found the report useful.
I do think it's possible to get JPEG working, but it hasn't yet been done.
Have you considered using the better documented STmicroelectronics VS6724?
It's harder to find, but it has much better documentation and it provides 2MP JPEG. However, it's been rumored that the VS6724 is being phased out (in favor of selling the camera in large quantities to large manufacturers).
See this thread for more info (including where to find):
viewtopic.php?t=10612
And you can google for the datasheet and more info.
I would definitely recommend using the AL440B FIFO instead of stand-alone RAM in order to make the memory management a lot easier. I investigated using stand-alone ram, but it's difficult to find counters that are wide enough and fast enough. And furthermore, the pin-outs on the counters seem to be unhelpful - they scramble the order of the output bits, which makes it more difficult to connect to the RAM. So a dedicated FIFO is definitely helpful. (Or you could use a FPGA in conjunction with stand-alone RAM.)
Someone asked me (in a PM) about whether the AL422B (3Mbits) could be used instead of the AL440B (4Mbits). I would say yes, but one downside of the AL422B is that it isn't quite big enough to buffer two CIF frames, while the AL440B is. But if someone gets JPEG working, that won't be an issue.
Good luck,
David
Edit: To be clear, I haven't used the VS6724. I am just envious of the better documentation.
I'm glad you found the report useful.
I do think it's possible to get JPEG working, but it hasn't yet been done.
Have you considered using the better documented STmicroelectronics VS6724?
It's harder to find, but it has much better documentation and it provides 2MP JPEG. However, it's been rumored that the VS6724 is being phased out (in favor of selling the camera in large quantities to large manufacturers).
See this thread for more info (including where to find):
viewtopic.php?t=10612
And you can google for the datasheet and more info.
I would definitely recommend using the AL440B FIFO instead of stand-alone RAM in order to make the memory management a lot easier. I investigated using stand-alone ram, but it's difficult to find counters that are wide enough and fast enough. And furthermore, the pin-outs on the counters seem to be unhelpful - they scramble the order of the output bits, which makes it more difficult to connect to the RAM. So a dedicated FIFO is definitely helpful. (Or you could use a FPGA in conjunction with stand-alone RAM.)
Someone asked me (in a PM) about whether the AL422B (3Mbits) could be used instead of the AL440B (4Mbits). I would say yes, but one downside of the AL422B is that it isn't quite big enough to buffer two CIF frames, while the AL440B is. But if someone gets JPEG working, that won't be an issue.
Good luck,
David
Edit: To be clear, I haven't used the VS6724. I am just envious of the better documentation.