McBSP Interface Signals and Registers
11-12
Table 11–6.
Pin Control Register (PCR) Field Descriptions (Continued)
Name
Section
Function
CLKRM
Receiver clock mode
Case 1: Digital loopback mode not set (DLB = 0) in SPCR
CLKRM = 0: Receive clock (CLKR) is an input driven by an external clock.
CLKRM = 1: CLKR is an output pin and is driven by the sample rate generator.
Case 2: Digital loopback mode set (DLB = 1) in SPCR
CLKRM = 0: Receive clock (not the CLKR pin) is driven by the transmit clock
(CLKX), which is based on the CLKXM bit in PCR. CLKR is in high im-
pedance.
CLKRM = 1: CLKR is an output pin and is driven by the transmit clock. The transmit
clock is derived from CLKXM bit in the PCR.
11.5.2.6
and
11.8
CLKXM
Transmitter clock mode
CLKXM = 0: Transmitter clock is driven by an external clock with CLKX as an input
pin.
CLKXM = 1: CLKX is an output pin and is driven by the internal sample rate genera-
tor.
During SPI mode (CLKSTP in SPCR is a nonzero value):
CLKXM = 0: McBSP is a slave and (CLKX) is driven by the SPI master in the system.
CLKR is internally driven by CLKX.
CLKXM = 1: McBSP is a master and generates the transmitter clock (CLKX) to drive
its receiver clock (CLKR) and the shift clock of the SPI-compliant slaves
in the system.
11.5.2.7
and
11.8
11.7
CLKS_STAT
CLKS pin status. Reflects the value on the CLKS pin when selected as a general-pur-
pose input.
11.8
DX_STAT
DX pin status. Reflects the value driven onto the DX pin when selected as a general-
purpose output.
11.8
DR_STAT
DR pin status. Reflects the value on the DR pin when selected as a general-purpose
input.
11.8
FSRP
Receive frame synchronization polarity
FSRP = 0: Frame synchronization pulse FSR is active high
FSRP = 1: Frame synchronization pulse FSR is active low
11.3.4.1
and
11.8
FSXP
Transmit frame synchronization polarity
FSXP = 0: Frame synchronization pulse FSX is active high
FSXP = 1: Frame synchronization pulse FSX is active low
11.3.4.1
and
11.8