ez80190 ZiLOG Semiconductor, ez80190 Datasheet - Page 82

• Manufacturer Part Number: ez80190
• Description: Ez80190 Microprocessor
• Manufacturer: ZiLOG Semiconductor

PS006613-0306
UART Interrupts
There are five different sources of interrupts from the UART. These five sources of
interrupts are:
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UART Transmitter Interrupt
The transmitter interrupt is generated if there is no data available for transmission.
This interrupt can be disabled using the individual interrupt enable bit, or cleared
by writing data into the UARTx_THR register.
UART Receiver Interrupts
A receiver interrupt can be generated by three possible events. The first event, a
receiver data ready interrupt event, indicates that one or more data bytes were
received and are ready to be read. If the FIFO is enabled, and the trigger level is
set, then this interrupt is generated if the number of bytes in the receive FIFO is
greater than or equal to the trigger level. If the FIFO is not enabled, the interrupt is
generated if the receive buffer contains a data byte. This interrupt is cleared by
reading the UARTx_RBR.
The second interrupt source is the receiver time-out. A receiver time-out interrupt
is generated when there are fewer data bytes in the receive FIFO than the trigger
level. There are no READs and writes to or from the receive FIFO for four consec-
utive byte times. After the receiver time-out interrupt is generated, it is cleared
only after it empties the entire receive FIFO.
The first two interrupt sources from the receiver (data ready and time-out) share
an interrupt enable bit.
The third source of a receiver interrupt is a line status error indicating an error in
byte reception. This error may result from:
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•
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An interrupt due to one of the above conditions is cleared when the UARTx_LSR
register is read. In the case of FIFO mode, a line status interrupt is generated only
Transmitter
Receiver (three different interrupts)
Modem status
Incorrect received parity
Incorrect framing (the stop bit is not detected by the receiver at the end of the
byte)
Receiver overrun condition
A Break Indication being detected on the receive data input
PRELIMINARY
Universal Asynchronous Receiver/Transmitter
eZ80190 Product Specification
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