G
gcary
I am writing some software that will interface with an FTDI USB chip
through the FTDI D2XX driver. Can anyone tell me a little bit about
where this driver sits in the Windows OS with respect to priority? I
assume it interfaces with the OS's USB drivers, so ultimately my
question pertains to the whole driver chain. When issuing a command to
write data, what other OS operations can hold off the write to the USB
bus? I can tolerate some delay, but probably not more than a half
second or so.
In the past I have experienced times where my computer seems to freeze
up for a couple of seconds while my hard drive spins up. I am worried
about what happens to USB transfers during times such as that. FTDI
doesn't have much information on their website. They have one app-note
named "AN232B-04_DataLatencyFlow.pdf" that describes the thing I am
worried about, but does not go into it very deeply. On page 4 of the
document, "2.2 Data Transfer Comparison", it reads "An example of
scheduling delays can be seen if an open application is dragged around
using the mouse".
Any help would be most appreciated. If there is a more appropriate
group to post this question to, please let me know.
Thanks in advance,
Greg
through the FTDI D2XX driver. Can anyone tell me a little bit about
where this driver sits in the Windows OS with respect to priority? I
assume it interfaces with the OS's USB drivers, so ultimately my
question pertains to the whole driver chain. When issuing a command to
write data, what other OS operations can hold off the write to the USB
bus? I can tolerate some delay, but probably not more than a half
second or so.
In the past I have experienced times where my computer seems to freeze
up for a couple of seconds while my hard drive spins up. I am worried
about what happens to USB transfers during times such as that. FTDI
doesn't have much information on their website. They have one app-note
named "AN232B-04_DataLatencyFlow.pdf" that describes the thing I am
worried about, but does not go into it very deeply. On page 4 of the
document, "2.2 Data Transfer Comparison", it reads "An example of
scheduling delays can be seen if an open application is dragged around
using the mouse".
Any help would be most appreciated. If there is a more appropriate
group to post this question to, please let me know.
Thanks in advance,
Greg