DXR1 to XSR1 copy (W1)
XRDY
DXR1 to XSR1 copy (W3)
Write to DXR1(W3)
Á
Á
Á
Á
Á
Á
Á
Á
W3
Á
Á
Á
Á
DX
RBR1 to DRR1 (W3)
Read From DRR1(W1)
RBR1 to DRR1 copy (W1)
RBR1 to DRR1 copy (W3)
Read From DRR1(W3)
Á
Á
Á
Á
Á
Á
Á
W3
Á
Á
Á
(d) XMCM = 11b, RPABLK = 00b, XPABLK = X, RCERA = 1010b, XCERA = 1000b:
Receive channels: 1 and 3 enabled; transmit channels: 1 and 3 enabled, but only 3 unmasked
Á
Á
Á
W1
Á
Á
Á
Á
Á
Á
Internal FS(R/X)
DR
RRDY
Write to DXR1(W3)
DXR1 to XSR1 copy(W0)
Write to DXR1(W1)
DXR1 to XSR1 copy(W1)
Write to DXR1(W2)
XRDY
DXR1 to XSR1 copy(W3)
DXR1 to XSR1 copy(W2)
W3
(c) XMCM = 10b, XPABLK = 00b, XCERA = 1010b: All channels enabled, only 1 and 3 unmasked
Internal FSX
Á
Á
Á
Á
Á
Á
Á
Á
W1
Á
Á
Á
Á
ÁÁ
ÁÁ
ÁÁ
ÁÁ
DX
(b) XMCM = 01b, XPABLK = 00b, XCERA = 1010b: Only channels 1 and 3 enabled and unmasked
DXR1 to XSR1 copy(W3)
Write to DXR1(W3)
XRDY
DXR1 to XSR1 copy(W1)
W3
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
DX
ÁÁ
ÁÁ
ÁÁ
ÁÁ
W1
Internal FSX
(a) XMCM = 00b: All channels enabled and unmasked
W3
W2
W1
W0
XRDY
DX
Internal FSX
DXR1 to XSR1 copy(W0)
Write to DXR1(W1)
DXR1 to XSR1 copy(W1)
Write to DXR1(W2)
DXR1 to XSR1 copy(W3)
DXR1 to XSR1 copy(W2)
Write to DXR1(W3)
ÁÁ
ÁÁ
ÁÁ
Á
Á
Á
SPI Operation Using the Clock Stop Mode
1071
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Multichannel Buffered Serial Port (McBSP)
Figure 15-35. Activity on McBSP Pins for the Possible Values of XMCM
15.7 SPI Operation Using the Clock Stop Mode
This section explains how to use the McBSP in SPI mode.
15.7.1 SPI Protocol
The SPI protocol is a master-slave configuration with one master device and one or more slave devices.
The interface consists of the following four signals:
•
Serial data input (also referred to as slave out/master in, or SOMI)