AT91CAP9S500A_1 Datasheet, PDF (521/1137 Pages) ATMEL Corporation – Customizable Microcontroller Processor

AT91CAP9S500A/AT91CAP9S250A
34.7.4 SPI Transmit Data Register
Name:
SPI_TDR
Addresses: 0xFFFA400C (0), 0xFFFA800C (1)
Access: Write-only
31
30
29
28
27
–
–
–
–
–
23
22
21
20
19
–
–
–
–
15
14
13
12
11
TD
7
6
5
4
3
TD
26
25
–
–
18
17
PCS
10
9
2
1
24
LASTXFER
16
8
0
• 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
transmit data register in a right-justified format.
• PCS: Peripheral Chip Select
This field is only used if Variable Peripheral Select is active (PS = 1).
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
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
This field is only used if Variable Peripheral Select is active (PS = 1).
6264C–CAP–24-Mar-09
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