RM0390 Rev 4 859/1328
RM0390 Serial peripheral interface/ inter-IC sound (SPI/I2S)
896
underflow error signal for slave operating in SPI mode, and that data from the slave are
always transacted and processed by the master even if the slave cannot not prepare them
correctly in time. It is preferable for the slave to use DMA, especially when data frames are
shorter and bus rate is high.
Each sequence must be encased by the NSS pulse in parallel with the multislave system to
select just one of the slaves for communication. In single slave systems, using NSS to
control the slave is not necessary. However, the NSS pulse can be used to synchronize the
slave with the beginning of each data transfer sequence. NSS can be managed either by
software or by hardware (see Section 26.3.4: Multi-master communication).
Refer to Figure 312 and Figure 313 for a description of continuous transfers in master / full-
duplex and slave full-duplex mode.
Figure 312. TXE/RXNE/BSY behavior in master / full-duplex mode (BIDIMODE=0,
RXONLY=0) in the case of continuous transfers
0,62026,LQ
7[EXIIHU
'$7$ [$
7;(IODJ
[)
%6<IODJ
[)
VRIWZDUH
ZULWHV[)
LQWR63,B'5
VRIWZDUHZDLWV
XQWLO7;( DQG
ZULWHV[)LQWR
63,B'5
VRIWZDUHZDLWV
XQWLO5;1(
DQGUHDGV[$
IURP63,B'5
VHWE\KDUGZDUH
FOHDUHGE\VRIWZDUH
VHWE\KDUGZDUH
FOHDUHGE\VRIWZDUH
VHWE\KDUGZDUH
VHWE\KDUGZDUH
6&.
'$7$ [$
'$7$ [$
UHVHWE\KDUGZDUH
([DPSOHLQ0DVWHUPRGHZLWK&32/ &3+$
[)
5;1(IODJ
ZULWH63,B'5
5[EXIIHU
VHWE\KDUGZDUH
0,62026,RXW
'$7$ [) '$7$ [)
'$7$ [)
UHDG63,B'5
[$
[$ [$
VRIWZDUHZDLWV
XQWLO7;( DQG
ZULWHV[)LQWR
63,B'5
VRIWZDUHZDLWV
XQWLO5;1(
DQGUHDGV[$
IURP63,B'5
VRIWZDUHZDLWV
XQWLO5;1(
DQGUHDGV[$
IURP63,B'5
E E E E E E E E E E E E E E E E E E E E E E E E
E E E E E E E E E E E E E E E E E E E E E E E E
FOHDUHGE\VRIWZDUH
DL