Serial peripheral interface / integrated interchip sound (SPI/I2S) RM0440
1754/2126 RM0440 Rev 4
Figure 584. Master full-duplex communication in packed mode
Assumptions for master full-duplex communication in packed mode example:
• Data size = 5 bit
• Read/write FIFO is performed mostly by 16-bit access
• FRXTH=0
If DMA is used:
• Number of Tx frames to be transacted by DMA is set to 3
• Number of Rx frames to be transacted by DMA is set to 3
• PSIZE for both Tx and Rx DMA channel is set to 16-bit
• LDMA_TX=1 and LDMA_RX=1
See also : Communication diagrams on page 1750 for details about common assumptions
and notes.
4 3 2 1
10
NSS
SCK
BSY
MOSI
5
SPE
TXE
00
11
11 00
FTLVL
DTx1-2
DTx3-4
01
10
00
10
00 00
RXNE
DRx1-2
DRx3-4
DRx5
FRLVL
DMA Tx TICF
DMA Rx TICF
11
2
3
4
5
Enable Tx/Rx DMA or interrupts
DMA or software control at Tx events
DMA or software control at Rx events
10
DTx5
10
7
4 3 2 1
5
4 3 2 1
5
4 3 2 1
5
4 3 2 1
5
DTx1-2 DTx3-4 DTx5
5 4 3 2
1
5 4 3 2
1
5 4 3 2
1
5 4 3 2
1 1
5 4 3 2
MISO
DRx1-2
DRx3-4 DRx5
01
FRTHX=1
01
00
01
8
3
MSv32125V2