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Section 3.3, 3 interrupt enable register (ier) – Texas Instruments TMS320DM643X DMP User Manual

Page 24

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Registers

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3.3

Interrupt Enable Register (IER)

The interrupt enable register (IER) is used to individually enable or disable each type of interrupt request
that can be generated by the UART. Each interrupt request that is enabled in IER is forwarded to the
CPU. IER is shown in

Figure 11

and described in

Table 9

.

Access considerations:

IER and DLH share one address. To read or modify IER, write 0 to the DLAB bit in LCR. When DLAB = 1,
all accesses at the shared address read or modify DLH.

DLH also has a dedicated address. If you use the dedicated address, you can keep DLAB = 0, so that IER
is always selected at the shared address.

Figure 11. Interrupt Enable Register (IER)

31

16

Reserved

R-0

15

4

3

2

1

0

Reserved

Rsvd

ELSI

ETBEI

ERBI

R-0

R/W-0

R/W-0

R/W-0

R/W-0

LEGEND: R/W = Read/Write; R = Read only; -n = value after reset

Table 9. Interrupt Enable Register (IER) Field Descriptions

Bit

Field

Value

Description

31-4

Reserved

0

Reserved

3

Reserved

0

Reserved. This bit must always be written with a 0.

2

ELSI

Receiver line status interrupt enable.

0

Receiver line status interrupt is disabled.

1

Receiver line status interrupt is enabled.

1

ETBEI

Transmitter holding register empty interrupt enable.

0

Transmitter holding register empty interrupt is disabled.

1

Transmitter holding register empty interrupt is enabled.

0

ERBI

Receiver data available interrupt and character timeout indication interrupt enable.

0

Receiver data available interrupt and character timeout indication interrupt is disabled.

1

Receiver data available interrupt and character timeout indication interrupt is enabled.

24

Universal Asynchronous Receiver/Transmitter (UART)

SPRU997C – December 2009

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