src/console.c File Reference

• console implementation file for newlib using UART

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#include <bf52x_uart.h>
#include <syscall.h>

Include dependency graph for console.c:

Defines
#define	CHARS_TX_MAX   128
Functions
static int	console_open (const char *path, int flags, int mode)
	Is not called for console.
static int	console_close (int fd)
	Is not called for console.
static int	console_write (int fd, const void *ptr, int len)
	Writes to uart console.
static int	console_read (int fd, void *ptr, int len)
	Reads from the console uart.
Variables
const devoptab_t	console_devoptab
	Console table.

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Detailed Description

• console implementation file for newlib using UART

Author:

Rohan Kangralkar

Date:

11/11/2011

LastChange:

Id

console.c 1069 2013-02-25 18:19:21Z ovaskevi

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Define Documentation

#define CHARS_TX_MAX   128

---

Function Documentation

static int console_close

(

int

fd

)

[static]

Is not called for console.

The newlib directly calls write and read

Parameters:

fd

file descriptor

Returns:

negative for console

static int console_open	(	const char *	path,
		int	flags,
		int	mode
	)			[static]

Is not called for console.

The newlib directly calls write and read

Parameters:

	path	file to be opened
	flags	opening flags
	mode	opening mode

Returns:

failure for console

static int console_read	(	int	fd,
		void *	ptr,
		int	len
	)			[static]

Reads from the console uart.

Parameters:

	fd	file descriptor
	ptr	pointer to buffer where the read data will be placed
	len	length og the expected data

Returns:

number of char read

The bf52x_uart_receive returns 0 for success and negative for failure For the newlib we have to return the number of char transfered. So we check the result and return binary value either fully transfered or nothing transfered.

Todo:

https://discussions.zoho.com/tlldesignbfn1/topic/return-value-for-transfers-of-data-over-uart

GS: Note bf52x_uart_receive has unsigned char as len paramter, will overflow if called from within scanf (with 1024). Hence, bf52x_uart_receive will see a 0 as len and return 0, which is improperly handled in newlibc. Workaround (given the todo above), always request len 1 only, and let newlibc iterate if it wants more chars.

static int console_write	(	int	fd,
		const void *	ptr,
		int	len
	)			[static]

Writes to uart console.

Parameters:

	fd	file descriptor
	ptr	pointer to the buffer to be tx
	len	length of data to be transfered

Returns:

number of bytes written.

The bf52x_uart_transmit returns 0 for success and negative for failure For the newlib we have to return the number of char transfered. So we check the result and return binary value either fully transfered or nothing transfered.

Todo:

https://discussions.zoho.com/tlldesignbfn1/topic/return-value-for-transfers-of-data-over-uart

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Variable Documentation

const devoptab_t console_devoptab

Initial value:

 { "console", console_open, console_close,
    console_write, console_read }

Console table.

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