DSPIC33FJ12MC202 Microchip Technology Inc., DSPIC33FJ12MC202 Datasheet - Page 113

• Manufacturer Part Number: DSPIC33FJ12MC202
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

9.4.5.2
Choosing the configuration requires review of all
peripheral pin selects and their pin assignments,
especially those that will not be used in the application.
In all cases, unused pin selectable peripherals should
be disabled completely. Unused peripherals should
have their inputs assigned to an unused RPn pin
function. I/O pins with unused RPn functions should be
configured with the null peripheral output.
The assignment of a peripheral to a particular pin does
not automatically perform any other configuration of the
pin’s I/O circuitry. This means adding a pin selectable
output to a pin can inadvertently drive an existing
peripheral input when the output is driven. Program-
mers must be familiar with the behavior of other fixed
peripherals that share a remappable pin, and know
when to enable or disable them. To be safe, fixed digital
peripherals that share the same pin should be disabled
when not in use.
9.4.5.3
Configuring a remappable pin for a specific peripheral
does not automatically turn that feature on. The
peripheral
operation and enabled, as if it were tied to a fixed pin.
Where
(immediately following device Reset and peripheral
configuration, or inside the main application routine)
depends on the peripheral and its use in the
application.
9.4.5.4
A final consideration is that peripheral pin select
functions
reconfigure pins with analog functions for digital I/O. If
a pin is configured as an analog input on device Reset,
it must be explicitly reconfigured as digital I/O when
used with a peripheral pin select.
9.4.5.5
Example 9-2 shows a configuration for bidirectional
communication with flow control using UART1. The
following input and output functions are used:
• Input Functions: U1RX, U1CTS
• Output Functions: U1TX, U1RTS
© 2007 Microchip Technology Inc.
this
neither
must
Choosing the Configuration
Pin Operation
Analog Functions
Configuration Example
happens
be
override
specifically
in
the
analog
application
configured
inputs
code
Preliminary
nor
for
dsPIC33FJ12MC201/202
EXAMPLE 9-2:
//*************************************
// Unlock Registers
//*************************************
asm volatile ( "mov #OSCCONL, w1
//***************************
// Configure Input Functions
// (See Table 9-1)
//***************************
//***************************
// Configure Output Functions
// (See Table 9-2)
//***************************
//*************************************
// Lock Registers
//*************************************
asm volatile ( "mov #OSCCONL, w1
//***************************
// Assign U1Rx To Pin RP0
//***************************
RPINR18bits.U1RXR = 0;
//***************************
// Assign U1CTS To Pin RP1
//***************************
RPINR18bits.U1CTSR = 1;
//***************************
// Assign U1Tx To Pin RP2
//***************************
RPOR1bits.RP2R = 3;
//***************************
// Assign U1RTS To Pin RP3
//***************************
RPOR1bits.RP3R = 4;
"mov.b w3, [w1]
"bclr OSCCON, 6");
"mov.b w3, [w1]
"bset OSCCON, 6");
"mov #0x46, w2
"mov #0x57, w3
"mov.b w2, [w1]
"mov #0x46, w2
"mov #0x57, w3
"mov.b w2, [w1]
CONFIGURING UART1
INPUT AND OUTPUT
FUNCTIONS
DS70265B-page 111
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