
Semtech 2006
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13-2
XE8805/05A
13.1 Features
Input / output port, 8 bits wide
Each bit can be set individually for input or output
13.2 Overview
Port C (PC) is a general purpose 8 bit input/output digital port.
Figure 13-1 shows its structure.
Figure 13-1: structure of Port C
13.3 Port C (PC) Operation
The direction of each bit within Port C (input or output) can be individually set by using the RegPCDir register. If
PCDir[x] = 1, the corresponding Port C pin becomes an output. After reset, Port C is in input mode (PCDir[x] are
reset to 0).
Output mode:
Data is stored in RegPCOut prior to output at Port C.
Input mode:
The status of Port C is available in RegPCIn (read only). Reading is always direct - there is no digital debounce
function associated with Port C. In case of possible noise on input signals, a software debouncer or an external
filter must be realized.
By default after reset, Port C is configured as an input port.
13.4 Register map
There are three registers in the Port C (PC), namely RegPCIn, RegPCOut and RegPCDir. Table 13-1 to Table
13-3 show the mapping of control bits and functionality of these registers.
Pos.
RegPCIn
Rw
Reset
Description
7-0
PCIn
r
-
pad PC input value
Table 13-1. RegPCIn
RegPCIn
RegPCOut
RegPCDir
8
Port C
Not
Recommended
for
New
Designs