Texas Instruments TMS320C3x - Manual (Page 402)

Serial Ports
12-23 Peripherals
Table 12–3. FSX/DX/CLKX Port-Control Register Bits Summary (Continued)
Abbreviation Description Name
Reset
Value
FSX FUNC 0 FSX function Controls the function of FSX.
If FSX FUNC = 0, FSX is configured as a general-purpose digital
I/O port.
If FSX FUNC = 1, FSX is configured as a serial port pin.
FSX I/O 0 FSX input/output
mode If FSX I/O = 0, FSX is configured as a general-purpose input
pin.
If FSX I/O = 1, FSX is configured as a general-purpose output
pin.
FSX DATOUT 0 FSX data output Data output on FSX when configured as general-purpose output.
FSX DATIN x † FSX data input Data input on FSX when configured as general-purpose input.
A write has no effect.
† x = 0 or 1
12.2.3 FSR/DR/CLKR Port-Control Register
This 32-bit port-control register is controlled by the function of the FSR, DR,
and CLKR pins. At reset, all bits are set to 0. The register is shown in
Figure 12–15. Table 12–4 shows the register bits, bit names, and bit functions.
Figure 12–15. FSR/DR/CLKR Port-Control Register
CLKR
FUNC
CLKR
I/O
CLKR
DATOUT
2
R/W
CLKR
DATIN
xx xx
FSR
DATIN
FSR
DATOUT
FSR
I/O
FSR
FUNC
DR
DATIN
DR
DATOUT
DR
I/O
DR
FUNC
31 16 15 12 11 10 9 8 7 6 5 4 3 1
R/W R/W R R/W R/W R R/W R/W
0
R R/W R/W
Notes: 1) R = read, W = write
2) xx = reserved bit, read as 0