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M0A21/M0A23 Series
May 06, 2022
Page
553
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
USCI Transmit Data Register (USPI_TXDAT)
Register
Offset
R/W
Description
Reset Value
USPI_TXDAT
U0x30
W
USCI Transmit Data Register
0x0000_0000
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
PORTDIR
15
14
13
12
11
10
9
8
TXDAT
7
6
5
4
3
2
1
0
TXDAT
Bits
Description
[31:17]
Reserved
Reserved.
[16]
PORTDIR
Port Direction Control
This bit field is only available while USCI operates in SPI protocol (FUNMODE = 0x1) with half-duplex transfer.
It is used to define the direction of the data port pin. When software writes USPI_TXDAT register, the transmit
data and its port direction are settled simultaneously.
0 = The data pin is configured as output mode.
1 = The data pin is configured as input mode.
[15:0]
TXDAT
Transmit Data
Software can use this bit field to write 16-bit transmit data for transmission. In order to avoid overwriting the
transmit data, user have to check TXEMPTY (USPI_BUFSTS[8]) status before writing transmit data into this
bit field.