515
Asynchronous Serial Interface (UARTA)
Chapter 16
Preliminary User’s Manual U17566EE1V2UM00
(5)
UAnSTR - UARTAn status register
The UAnSTR register is an 8-bit register that displays the UARTAn transfer
status and reception error contents.
Access
This register can be read or written in 8-bit or 1-bit units.
Address
<base> + 4
H
Initial Value
00
H
. This register is cleared by any reset.
The initialization conditions are shown below.
Register/Bit
Initialization conditions
UAnSTR register
•
Reset
•
UAnCTL0.UAnPWR = 0
UAnTSF bit
•
UAnCTL0.UAnTXE = 0
UAnPE, UAnFE, UAnOVE bits
•
0 write
•
UAnCTL0.UAnRXE = 0
7
6
5
4
3
2
1
0
UAnTSF
0
0
0
0
UAnPE
UAnFE
UAnOVE
R
R/W
R/W
R/W
R/W
R/W
a
a)
These bits can only be cleared by writing, They cannot be set by writing 1 (even if
1 is written, the value is retained).
R/W
a
R/W
a
Table 16-5
UAnSTR register contents (1/2)
Bit position
Bit name
Function
7
UAnTSF
Transfer status flag:
0: – When the UAnPWR bit = 0 or the UAnTXE bit = 0 has been set.
– When, following transfer completion, there was no next data transfer from
UAnTX register
1: Write to UAnTXB bit
The UAnTSF bit is always 1 when performing continuous transmission. When
initializing the transmission unit, check that the UAnTSF bit = 0 before performing
initialization. The transmit data is not guaranteed when initialization is performed
while the UAnTSF bit = 1.
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