7
3. You can select “
FIFOs
” change the length of receiver and transmitter FIFO.
This page is used to configure the FIFO trigger levels, i.e. at what fill levels the device will generate an
interrupt, or apply automatic flow control. In addition, the FIFO can be completely disabled; although this is
not recommended for normal operation. The four sliders allow adjustment of the various trigger levels in
550 and 950 modes. These are described below:
Transmitter FIFO interrupt trigger level - When the level of data in the transmit FIFO falls below this
value, a transmitter interrupt is triggered. Setting this value to zero will not trigger an interrupt until the
transmitter is completely idle.
Receiver FIFO interrupt trigger level - When the level of data in the receiver FIFO reaches this
value, a receiver data interrupt is triggered.
Flow On flow-control limit - When the level of data in the receiver FIFO reaches this value as data
is read from the FIFO, a handshake is triggered to instruct the remote transmitter that it is free to
transmit data (E.g. Transmit an XON character to the remote machine).
Flow Off flow-control limit - When the level of data in the receiver FIFO reaches this value as it fills
up, a handshake is triggered to instruct the remote transmitter to stop sending data as the FIFO is
becoming full. (E.g. Transmit an XOFF character to the remote machine).
The FIFO trigger levels can be fine tuned to gain optimum performance, depending on system
performance, baud rate used, levels of serial traffic etc.
