40.8.4 SPI Transmit Data Register
| Name: | SPI_TDR |
| Offset: | 0x0C |
| Reset: | – |
| Property: | Write-only |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| LASTXFER | |||||||||
| Access | W | ||||||||
| Reset | – |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| PCS[3:0] | |||||||||
| Access | W | W | W | W | |||||
| Reset | – | – | – | – | |||||
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| TD[15:8] | |||||||||
| Access | W | W | W | W | W | W | W | W | |
| Reset | – | – | – | – | – | – | – | – | |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| TD[7:0] | |||||||||
| Access | W | W | W | W | W | W | W | W | |
| Reset | – | – | – | – | – | – | – | – | |
Bit 24 – LASTXFER Last Transfer
This field is only used if variable peripheral select is active (SPI_MR.PS = 1).
| Value | Description |
|---|---|
| 0 | No effect |
| 1 | The current NPCS is deasserted after the transfer of the character written in TD. When SPI_CSRx.CSAAT is set, the communication with the current serial peripheral can be closed by raising the corresponding NPCS line as soon as TD transfer is completed. |
Bits 19:16 – PCS[3:0] Peripheral Chip Select
This field is only used if variable peripheral select is active (SPI_MR.PS = 1).
If SPI_MR.PCSDEC = 0:
PCS = xxx0 NPCS[3:0] = 1110
PCS = xx01 NPCS[3:0] = 1101
PCS = x011 NPCS[3:0] = 1011
PCS = 0111 NPCS[3:0] = 0111
PCS = 1111 forbidden (no peripheral is selected)
(x = don’t care)
If SPI_MR.PCSDEC = 1:
NPCS[3:0] output signals = PCS.
Bits 15:0 – TD[15:0] Transmit Data
Data to be transmitted by the SPI interface is stored in this register. Information to be transmitted must be written to this register in a right-justified format.