UART Modules
Freescale Semiconductor
26-13
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
26.3.9
UART Auxiliary Control Register (UACRn)
The UACRs control the input enable.
26.3.10 UART Interrupt Status/Mask Registers (UISRn/UIMRn)
The UISRs provide status for all potential interrupt sources. UISR
n
contents are masked by UIMR
n
. If
corresponding UISR
n
and UIMR
n
bits are set, internal interrupt output is asserted. If a UIMR
n
bit is
cleared, state of the corresponding UISR
n
bit has no effect on the output.
The UISR
n
and UIMR
n
registers share the same space in memory. Reading this register provides the user
with interrupt status, while writing controls the mask bits.
Table 26-8. UIPCRn Field Descriptions
Field
Description
7–5
Reserved
4
COS
Change of state (high-to-low or low-to-high transition).
0 No change-of-state since the CPU last read UIPCRn. Reading UIPCRn clears UISRn[COS].
1 A change-of-state longer than 25–50
μ
s occurred on the UCTSn input. UACRn can be programmed to generate
an interrupt to the CPU when a change of state is detected.
3–1
Reserved
0
CTS
Current state of clear-to-send. Starting two serial clock periods after reset, CTS reflects the state of UCTSn. If
UCTSn is detected asserted at that time, COS is set, which initiates an interrupt if UACRn[IEC] is enabled.
0 The current state of the UCTSn input is asserted.
1 The current state of the UCTSn input is deasserted.
IPSBAR
Offset:
0x00_0210 (UACR0)
0x00_0250 (UACR1)
0x00_0290 (UACR2)
Access: User write-only
7
6
5
4
3
2
1
0
R
W
0
0
0
0
0
0
0
IEC
Reset:
0
0
0
0
0
0
0
0
Figure 26-11. UART Auxiliary Control Registers (UACRn)
Table 26-9. UACRn Field Descriptions
Field
Description
7–1
Reserved, must be cleared.
0
IEC
Input enable control.
0 Setting the corresponding UIPCRn bit has no effect on UISRn[COS].
1 UISRn[COS] is set and an interrupt is generated when the UIPCRn[COS] is set by an external transition on the
UCTSn input (if UIMRn[COS] = 1).
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60