Datasheet

532
14.4 SCI Interrupt Sources and the DMAC/DTC
The SCI has four interrupt sources: transmit-end (TEI), receive-error (ERI), receive-data-full
(RxI), and transmit-data-empty (TxI). Table 14.12 lists the interrupt sources and indicates their
priority. These interrupts can be enabled and disabled by the TIE, RIE, and TEIE bits in the serial
control register (SCR). Each interrupt request is sent separately to the interrupt controller.
TxI is requested when the TDRE bit in the SSR is set to 1. TxI can start the direct memory access
controller (DMAC) or the data transfer controller (DTC) to transfer data. TDRE is automatically
cleared to 0 when the DMAC or the DTC writes data in the transmit data register (TDR).
RxI is requested when the RDRF bit in the SSR is set to 1. RxI can start the DMAC or the DTC to
transfer data. RDRF is automatically cleared to 0 when the DMAC or the DTC reads the receive
data register (RDR).
ERI is requested when the ORER, PER, or FER bit in the SSR is set to 1. ERI cannot start the
DMAC or the DTC.
TEI is requested when the TEND bit in the SSR is set to 1. TEI cannot start the DMAC or the
DTC. Where the TxI interrupt indicates that transmit data writing is enabled, the TEI interrupt
indicates that the transmit operation is complete.
Table 14.12 SCI Interrupt Sources
Interrupt Source Description DMAC/DTC Activation Priority
ERI Receive error (ORER, PER, or FER) No High
RxI Receive data full (RDRF) Yes
TxI Transmit data empty (TDRE) Yes
TEI Transmit end (TEND) No Low