usb-exchange.h File Reference

Cascoda posix exchange for communicating with ca821x via usb. More...

#include "ca821x-posix/ca821x-types.h"
#include "ca821x_api.h"

Include dependency graph for usb-exchange.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	TEST_ENABLE   1

Enumerations
enum	usb_exchange_errors { usb_exchange_err_usb = 1 , usb_exchange_err_ca821x , usb_exchange_err_generic }

Functions
ca_error	usb_exchange_init (ca821x_errorhandler callback, const char *path, struct ca821x_dev *pDeviceRef, char *serial_num)
	Initialise the usb exchange. More...
void	usb_exchange_deinit (struct ca821x_dev *pDeviceRef)
	Deinitialise the usb exchange, so that it can be reinitialised by another process, or reopened later. More...
int	usb_exchange_reset (unsigned long resettime, struct ca821x_dev *pDeviceRef)
	Send a hard reset to the ca821x. More...
ca_error	usb_exchange_enumerate (util_device_found aCallback, void *aContext)
	Function to enumerate all of the USB connected devices, calling aCallback with a struct describing each one. More...
void	test_frag_loopback ()
	Run to test fragmentation. More...

Detailed Description

Cascoda posix exchange for communicating with ca821x via usb.

Macro Definition Documentation

TEST_ENABLE

#define TEST_ENABLE   1

Enumeration Type Documentation

usb_exchange_errors

enum usb_exchange_errors

Enumerator
usb_exchange_err_usb	Usb error - probably device removed and going to have to crash safely.
usb_exchange_err_ca821x	ca821x error - ca821x has been reset
usb_exchange_err_generic

Function Documentation

test_frag_loopback()

void test_frag_loopback

(

)

Run to test fragmentation.

Crashes upon fail.

usb_exchange_deinit()

void usb_exchange_deinit

(

struct ca821x_dev *

pDeviceRef

)

Deinitialise the usb exchange, so that it can be reinitialised by another process, or reopened later.

Parameters

pDeviceRef

Pointer to initialised ca821x_device_ref struct

usb_exchange_enumerate()

ca_error usb_exchange_enumerate	(	util_device_found	aCallback,
		void *	aContext
	)

Function to enumerate all of the USB connected devices, calling aCallback with a struct describing each one.

The struct passed to aCallback will only be valid for the duration that the function is called. This function will not return until every callback has been called.

Parameters

aCallback	The callback to call with each result
aContext	The generic void pointer to provide to the callback when it is called

Return values

CA_ERROR_SUCCESS	Enumeration successful
CA_ERROR_NOT_FOUND	No devices found

usb_exchange_init()

ca_error usb_exchange_init	(	ca821x_errorhandler	callback,
		const char *	path,
		struct ca821x_dev *	pDeviceRef,
		char *	serial_num
	)

Initialise the usb exchange.

If callback is specified, then it will be used to report any fatal errors back to the application, which can react as required (i.e. crash gracefully or attempt to reset the ca821x)

If path is specified, then the exchange will attempt to open that device, and fail if it cannot. The path of a device can be obtained with usb_exchange_enumerate.

If serial_num is specified, then the exchange will run an additional check when iterating through all devices, looking for one with matching serial number; Otherwise it will carry out the normal iteration and try to open the first available device.

Parameters

[in]	callback	Function pointer to an error-handling callback (can be NULL)
[in]	path	String representing an exchange & system specific path to a device (can be NULL)
[in]	pDeviceRef	Pointer to initialised ca821x_device_ref struct
[in]	serial_num	Serial number of the target device (can be NULL)

Return values

CA_ERROR_SUCCESS	success
CA_ERROR_NOT_FOUND	No available devices found (or device at path not found)
CA_ERROR_NO_ACCESS	The specified path cannot be opened (e.g. no permissions, already in use)
CA_ERROR_ALREADY	The pDeviceRef is already initialised

usb_exchange_reset()

int usb_exchange_reset	(	unsigned long	resettime,
		struct ca821x_dev *	pDeviceRef
	)

Send a hard reset to the ca821x.

This should not be necessary, but is provided in case the ca821x becomes unresponsive to spi.

Parameters

[in]	resettime	The length of time (in ms) to hold the reset pin active for. 1ms is usually a suitable value for this.
[in]	pDeviceRef	Pointer to initialised ca821x_device_ref struct