Computer Hardware User's Guide

Serial Ports
12-24
Table 12–4. FSR/DR/CLKR Port-Control Register Bits Summary
Abbreviation
Reset
Value
Name Description
CLKR FUNC 0 Clock receive
function
Controls the function of CLKR.
If CLKR FUNC = 0, CLKR is configured as a general-purpose
digital I/O port.
If CLKR FUNC = 1, CLKR is configured as a serial port pin.
CLKR I/O 0 Clock receive
input/output
mode
If CLKR I/O = 0, CLKR is configured as a general-purpose input
pin.
If CLKR I
/O = 1, CLKR is configured as a general-purpose output
pin.
CLKR DATOUT 0 Clock receive
data output
Data output on CLKR when configured as general-purpose
output.
CLKR DATIN x
†
Clock receive
data input
Data input on CLKR when configured as general-purpose input.
A write has no effect.
DR FUNC 0 DR function Controls the function of DR.
If DR FUNC = 0, DR is configured as a general-purpose digital
I/O port.
If DR FUNC = 1, DR is configured as a serial port pin.
DR I
/O 0 DR input/output
mode
If DR I/O = 0, DR is configured as a general-purpose input pin.
If DR I
/O = 1, DR is configured as a general-purpose output pin.
DR DATOUT 0 DR data output Data output on DR when configured as general-purpose output.
DR DATIN x
†
DR data input Data input on DR when configured as general-purpose input.
A write has no effect.
FSR FUNC 0 FSR function FSR FUNC controls the function of FSR.
If FSR FUNC = 0, FSR is configured as a general-purpose digital
I/O port.
If FSR FUNC = 1, FSR is configured as a serial port pin.
FSR I
/O 0 FSR input/output
mode
If FSR I/O = 0, FSR is configured as a general-purpose input
pin.
If FSR I
/O = 1, FSR is configured as a general-purpose output
pin.
FSR DATOUT 0 FSR data output Data output on FSR when configured as general-purpose output.
FSR DATIN x
†
FSR data input Data input on FSR when configured as general-purpose input.
A write has no effect.
†
x = 0 or 1.