4.3 Alternate Function Redirection
Many I/O pins, in addition to their normal I/O function, also serve the alternate function for internal peripherals.
For the peripherals Keypad interrupt, PCA, SPI and UART2, Port 2 and Port 1 serve the alternate function in the
default state. However, the user may select Port 4 to serve their alternate function by setting the corresponding
control bits P4KB, P4PCA, P4SPI and P4S2 in AUXR1 register. It is especially useful when the package more
than 40 pins is adopted. Note that only one of the four control bits can be set at any time.
AUXR1 (Address=8EH, Auxiliary Register1, Reset Value=0000,0000B)
7
6
5
4
3
2
1
0
P4KB
P4PCA
P4SPI
P4S2
GF2
-
-
DPS
P4KB: When set, the Keypad interface is directed to P4, as shown below.
‘KBI7’ function in P2.7 is moved to P4.7.
‘KBI6’ function in P2.6 is moved to P4.6.
‘KBI5’ function in P2.5 is moved to P4.5.
‘KBI4’ function in P2.4 is moved to P4.4.
‘KBI3’ function in P2.3 is moved to P4.3.
‘KBI2’ function in P2.2 is moved to P4.2.
‘KBI1’ function in P2.1 is moved to P4.1.
‘KBI0’ function in P2.0 is moved to P4.0.
P4PCA: When set, the PCA interface is directed to P4, as shown below.
‘ECI’ function in P1.1 is moved to P4.1.
‘CEX0’ function in P1.2 is moved to P4.2.
‘CEX1’ function in P1.3 is moved to P4.3.
‘CEX2’ function in P1.4 is moved to P4.4.
‘CEX3’ function in P1.5 is moved to P4.5
‘CEX4’ function in P1.6 is moved to P4.6.
‘CEX5’ function in P1.7 is moved to P4.7.
P4SPI: When set, the SPI interface is directed to P4, as shown below.
‘/SS’ function in P1.4 is moved to P4.4.
‘MOSI’ function in P1.5 is moved to P4.5.
‘MISO’ function in P1.6 is moved to P4.6.
‘SPICLK’ function in P1.7 is moved to P4.7.
P4S2: When set, the UART2 interface is directed to P4, as shown below.
‘S2RXD’ function in P1.2 is moved to P4.2.
‘S2TXD’ function in P1.3 is moved to P4.3.
17
MPC82G516A Data Sheet
MEGAWIN
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