Serial Ports
12-22

12.2.2 FSX/DX/CLKX Port-Control Register

This 32-bit port-control register controls the function of the serial port FSX, DX,

and CLKX pins. The register is shown in Figure 12–14. Table 12–3 shows the

register bits, bit names, and bit functions.

Figure 12–14. FSX/DX/CLKX Port-Control Register
31–16 15–12 11 10 9 8 7 6 5 4 3 2 1 0
xx xx FSX
DATIN FSX
DATOUT FSX
I/O FSX
FUNC DX
DATIN DX
DATOUT DX
I/O DX
FUNC CLKX
DATIN CLKX
DATOUT CLKX
I/O CLKX
FUNC
R R/W R/W R/W R R/W R/W R/W R R/W R/W R/W
Notes: 1) R = read, W = write.
2) xx = reserved bit, read as 0.
Table 12–3. FSX/DX/CLKX Port-Control Register Bits Summary
Abbreviation Reset
Value Name Description
CLKX FUNC 0Clock transmit
function Controls the function of CLKX.
If CLKX FUNC = 0, CLKX is configured as a general-purpose
digital I/O port.
If CLKX FUNC = 1, CLKX is configured as a serial port pin.
CLKX I/O 0 Clock transmit
input/output
mode
If CLKX I/O = 0, CLKX is configured as a general-purpose input
pin.
If CLKX I/O = 1, CLKX is configured as a general-purpose output
pin.
CLKX DATOUT 0 Clock transmit
data ouput Data output on CLKX when configured as general-purpose
output.
CLKX DATIN xClock transmit
data input Data input on CLKX when configured as general-purpose input.
A write has no effect.
DX FUNC 0 DX function DXFUNC controls the function of DX.
If DXFUNC = 0, DX is configured as a general-purpose digital
I/O port.
If DXFUNC = 1, DX is configured as a serial port pin.
DX I/O 0 DX input/output
mode If DX I/O = 0, DX is configured as a general-purpose input pin.
If DX I/O = 1, DX is configured as a general-purpose output pin.
DX DATOUT 0 DX data output Data output on DX when configure d as general-purpose output.
DX DATIN xDX data input Data input on DX when configured as general-purpose input.
A write has no effect.
x = 0 or 1