Atmel SAM4L Xplained Pro Starter Kit Atmel ATSAM4L-XSTK ATSAM4L-XSTK Data Sheet
Product codes
ATSAM4L-XSTK
681
42023E–SAM–07/2013
ATSAM4L8/L4/L2
26.8.4
Transmit Data Register
Name: TDR
Access Type: Write-only
Offset:
0x0C
Reset Value:
0x00000000
• LASTXFER: Last Transfer
1: The current NPCS will be deasserted after the character written in TD has been transferred. When CSRn.CSAAT is one, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
0: Writing a zero to this bit has no effect.
This field is only used if Variable Peripheral Select is active (MR.PS = 1).
• PCS: Peripheral Chip Select
If PCSDEC = 0:
PCS = xxx0NPCS[3:0] = 1110
PCS = xx01NPCS[3:0] = 1101
PCS = x011NPCS[3:0] = 1011
PCS = 0111NPCS[3:0] = 0111
PCS = 1111forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS
This field is only used if Variable Peripheral Select is active (MR.PS = 1).
• TD: Transmit Data
Data to be transmitted by the SPI Interface is stored in this register. Information to be transmitted must be written to the TDR
register in a right-justified format.
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
LASTXFER
23
22
21
20
19
18
17
16
-
-
-
-
PCS
15
14
13
12
11
10
9
8
TD[15:8]
7
6
5
4
3
2
1
0
TD[7:0]