Bits Used to Enable and Configure the Clock Stop Mode
SPI Operation Using the Clock Stop Mode
6-4
SPRU592E
6.3 Bits Used to Enable and Configure the Clock Stop Mode
The bits required to configure the McBSP as an SPI device are introduced in
Table 6
2 shows how the various combinations of the CLKSTP bit
and the polarity bits CLKXP and CLKRP create four possible clock stop mode
configurations. The timing diagrams in section 6.4 show the effects of
CLKSTP, CLKXP, and CLKRP.
Table 6
−
1. Bits Used to Enable and Configure the Clock Stop Mode
Bit Field
Description
CLKSTP bits of SPCR1
Use these bits to enable the clock stop mode and to
select one of two timing variations.
CLKXP bit of PCR
This bit determines the polarity of the CLKX signal.
CLKRP bit of PCR
This bit determines the polarity of the CLKR signal.
CLKXM bit of PCR
This bit determines whether CLKX is an input signal
(McBSP as slave) or an output signal (McBSP as
master).
XPHASE
bit
of
XCR2
You must use a single-phase transmit frame
(XPHASE = 0).
RPHASE bit of RCR2
You must use a single-phase receive frame
(RPHASE = 0).
XFRLEN1 bits of XCR1
You must use a transmit frame length of 1 serial word
(XFRLEN1 = 0).
RFRLEN1 bits of RCR1
You must use a receive frame length of 1 serial word
(RFRLEN1 = 0).
XWDLEN1 bits of XCR1
The XWDLEN1 bits determine the transmit packet
length. XWDLEN1 must be equal to RWDLEN1
because in the clock stop mode, the McBSP transmit
and receive circuits are synchronized to a single clock.
RWDLEN1 bits of RCR1
The RWDLEN1 bits determine the receive packet
length. RWDLEN1 must be equal to XWDLEN1
because in the clock stop mode, the McBSP transmit
and receive circuits are synchronized to a single clock.
Summary of Contents for TMS320VC5509
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Page 43: ...McBSP Operation 2 20 SPRU592E This page is intentionally left blank ...
Page 105: ...SPI Operation Using the Clock Stop Mode 6 16 SPRU592E This page is intentionally left blank ...
Page 187: ...Transmitter Configuration 8 40 SPRU592E This page is intentionally left blank ...
Page 191: ...General Purpose I O on the McBSP Pins 9 4 SPRU592E This page is intentionally left blank ...
Page 201: ...Emulation Power and Reset Considerations 10 10 SPRU592E ...
Page 207: ...Data Packing Examples 11 6 SPRU592E This page is intentionally left blank ...
Page 273: ...McBSP Register Worksheet 13 14 SPRU592E This page is intentionally left blank ...