URL:
<http://savannah.nongnu.org/bugs/?25300>
Summary: Additional i/o port names
Project: AVR C Runtime Library
Submitted by: None
Submitted on: Вск 11 Янв 2009 11:46:27
Category: Feature Request
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Header files
Status: None
Percent Complete: 0%
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Release: Any
Fixed Release: None
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Details:
It's a common thing when single pin on a device represents several features,
for example atmega8:
PORTB:
PB5 can be used as regular i/o port or SCK for SPI interface
PB4 can be used as regular i/o port or MISO for SPI interface
PB3 can be used as regular i/o port or MOSI for SPI interface
PB2 can be used as regular i/o port or SS for SPI interface
PORTD:
PD0 can be used as regular i/o port or RX for usart
PD1 can be used as regular i/o port or TX for usart
etc...
Almost every pin have several meanings. So if I'm trying to build software
wich communicates using for example SPI interface, i have to use some of i/o
ports in another meaning(write logical 1/0 to SS pin to select/deselect slave
device) So i think it's a good idea to put such definitions to headers:
for example:
#define SS PB2
#define MOSI PB3
#define MISO PB4
#define SCK PB5
#define SPI_PORT PORTB
#define RX PD0
#define TX PD1
#define USART_PORT PORTD
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