Texas Instruments CC3235 SimpleLink Series - PDIR Register; PDIR Register Field Descriptions

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SWRU543–January 2019
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Inter-Integrated Sound (I2S) Multichannel Audio Serial Port
12.5.3 PDIR Register (Offset = 14h) [reset = 0h]
PDIR is shown in Figure 12-6 and described in Table 12-8.
Return to Summary Table.
The pin direction register (PDIR) specifies the direction of AXR[n], ACLKX, AHCLKX, AFSX, ACLKR,
AHCLKR, and AFSR pins as either input or output pins.
Regardless of the pin function register (PFUNC) setting, each PDIR bit must be set to 1 for the specified
pin to be enabled as an output, and each PDIR bit must be cleared to 0 for the specified pin to be an
input.
For example, if the I2S is configured to use an internally-generated bit clock and the clock is to be driven
out to the system, the PFUNC bit must be cleared to 0 (McASP function) and the PDIR bit must be set to
1 (an output).
When AXR[n] is configured to transmit, the PFUNC bit must be cleared to 0 (McASP function) and the
PDIR bit must be set to 1 (an output). Similarly, when AXR[n] is configured to receive, the PFUNC bit must
be cleared to 0 (McASP function) and the PDIR bit must be cleared to 0 (an input).
CAUTION
Writing to Reserved Bits: Writing a value other than 0 to reserved bits in this
register may cause improper device operation. This includes bits that are not
implemented on a particular DSP.
Figure 12-6. PDIR Register
31 30 29 28 27 26 25 24
AFSR AHCLKR ACLKR AFSX AHCLKX ACLKX AMUTE RESERVED
R/W-0h R/W-0h R/W-0h R/W-0h R/W-0h R/W-0h R/W-0h R-0h
23 22 21 20 19 18 17 16
RESERVED
R-0h
15 14 13 12 11 10 9 8
AXR[15-0]
R/W-0h
7 6 5 4 3 2 1 0
AXR[15-0]
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 12-8. PDIR Register Field Descriptions
Bit Field Type Reset Description
31 AFSR R/W 0h
Determines if AFSR pin functions as an input or output.
0h = Pin functions as input.
1h = Pin functions as output.
30 AHCLKR R/W 0h
Determines if AHCLKR pin functions as an input or output.
0h = Pin functions as input.
1h = Pin functions as output.
29 ACLKR R/W 0h
Determines if ACLKR pin functions as an input or output.
0h = Pin functions as input.
1h = Pin functions as output.