Thanks for replying, Before I want to even consider doing all that, I need a suspicion of mine answered. I think that the Canon 4200F is nearly interchangeable with the 4400F, and can use its already written driver.
Can you guide me on how I would use the driver for this scanner? Thanks, -[K] IMSOASIAN On 11/22/21, Ralph Little <[email protected]> wrote: > Hi, > > On 2021-11-20 2:56 p.m., LUH LAH wrote: >> Hello there! >> >> It's been over a month since I last inquired about this, but I have an >> update and need some more guidance. >> >> I installed Windows 7 on another computer I had and captured packets >> from when I pressed the 'Scan' button in the CanoScan tool. >> >> Now that I've got the packets captured in a .pcapng file >> (https://drive.google.com/file/d/1E0zErjd0PB3Ggmeop6iI43Gi0SCZ8K9m/view?usp=sharing), >> how do I analyze the packets and figure out the USB chip model? >> >> Thanks, >> >> -[K] IMSOASIAN >> >> >> (This is a continuation of a previous thread. Said thread can be found >> here: >> https://alioth-lists.debian.net/pipermail/sane-devel/2021-October/thread.html >> [Look for a thread mentioning a Canon 4200F by LUH LAH]) >> > This is a difficult question to answer simply. > > The first step would be to determine if the protocol is supported by an > existing backend. > Unfortunately, we do not have much documentation about the protocols > that are currently supported with which to compare. > We usually get hints based on the chippery found inside. For this > machine, it sounds like it is just a standard set of components that > doesn't give us much of a clue. > > It might be that since this is a Canon scanner, then it might borrow > some heritage from one of their other models from the time that are not > using one of the standard scanner all-in-one chips. > > Failing that, if you want to start to look at writing a backend for this > scanner from scratch, you need to look in the USB conversation for the > various parts of the scanning process and the conversation would > typically follow the following sequence: > > 1) Reset: some sequences to get the scanner into a known state. It might > start with a sequence intended to get the scanner's attention. > 2) Setting of parameters followed by calibration operations. Generally > includes scans of a black and white area under the case to get the > proper balance for each scan head pixel, since there is typically > variation between them so correction is required. If the scanner is > doing this, the you will notice the scan head make some short passes > before the actual scan. > 3) Scan proper: setting up of motor acceleration table, setting > parameters for the scan head etc and the proceeding with the scan > itself. This phase will be *very* obvious looking at the trace as there > will be large blocks of data being transferred to the PC. > 4) Instructions to bring the scanning head back to the parking position. > > I would start with trying to split the trace into those rough sections. > One initial thing you can try is to extract the bytes from the trace > during the scanning phase, assemble them into a file and try to view > them as a graphic to figure out the format. > Dropping the bytes into a PNM format file is handy and then you can > experiment with the header parameters to get an image that looks correct. > > Cheers, > Ralph >
