There is a 24 Rx frame communication frame buffer with FIFO structure. Therefore, users can continuously send data to our module as long as the Rx frame does not overflow.
The display module has a hardware pin(namly /Busy in user interface) to indicate the FIFO status. Normally, /Busy pin keeps high (RS232 is negative); when there is only one frame buffer area left, /Busy pin will go to low level.(RS232 is positive)
For general applications, as the processing speed is very fast, it is not necessary for the users to judge the status of /Busy pin.
However, for applications of sending multiple date frame in a short time, such as to rapidly refresh hundreds of monitor parameters at the same time, users are advised to use /Busy signal for controlling serial port; and when /Busy signal is low, stop sending data to HMI.
If "drop-frame" phenomenon (some data do not display) occurs in the process of using
Display module, overflowing of buffers may be the reason. Oscilloscope can help to inspect whether Busy signal alters. If so, slow down the transmitting speed or add hardware inspection to deal with Busy signal.
没有评论:
发表评论