UM10850
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User manual
Rev. 2.4 — 13 September 2016
357 of 464
NXP Semiconductors
UM10850
Chapter 24: LPC5410x System FIFO for Serial Peripherals
When DMA is being used to receive data from the FIFO, the timeout has a limited value. A
DMA request is always generated whenever the FIFO is not empty, so there should never
be idle data in the FIFO for any length of time. The TimeoutContOnEmpty mode could
potentially still be used to indicate an idle receiver.
24.6.4 Transmitting data
DMA can be configured to send transmit data to a peripheral FIFO and generate an
interrupt when a transfer is competed. An interrupt service routine could send transmit
data instead of DMA. An ISR could always send data until the transmit FIFO is full, if
enough is available. When a complete data packet has been written to the transmit FIFO,
the interrupt could be disabled to prevent further interrupts.
24.6.5 Channel Priority
Receive requests are given priority over transmit requests, in order to minimize potential
loss of data. A simple first come, first served priority scheme is used to manage
overlapping service requests within the two aforementioned groups. Simultaneously
asserted requests within the same group are handled by giving priority to the lower
numbered channel.
24.6.6 Errors
A bus error flag is provided for each peripheral FIFO. This flag simply reflects any internal
bus error during a System FIFO data transfer. It is very unlikely that a bus error will occur
in practice, but potentially problematic if not reported at all.