SMB clock port control

Description

The SMB clock port (J62) may be used to synchronize sampling on multiple devices, or to generate an arbitrary clock output for a different device.

For MIMO configurations, one device is the clock "master" and outputs its 38.4 MHz reference on this port. The clock "slave" devices configure the SMB port as an input and expect to see this 38.4 MHz reference on this port. This implies that the "master" must be configured first.

Alternatively, this port may be used to generate an arbitrary clock signal for use with other devices via the bladerf_set_smb_frequency() and bladerf_set_rational_smb_frequency() functions.

Warning

Do not use these functions when operating an expansion board. A different clock configuration is required for the XB devices which cannot be used simultaneously with the SMB clock port.

These functions are thread-safe.

Enumerations
enum	bladerf_smb_mode {   BLADERF_SMB_MODE_INVALID = -1 , BLADERF_SMB_MODE_DISABLED , BLADERF_SMB_MODE_OUTPUT , BLADERF_SMB_MODE_INPUT ,   BLADERF_SMB_MODE_UNAVAILBLE }

Macros
#define	BLADERF_SMB_FREQUENCY_MAX   200000000u
#define	BLADERF_SMB_FREQUENCY_MIN   ((38400000u * 66u) / (32 * 567))

Functions
API_EXPORT int CALL_CONV	bladerf_set_smb_mode (struct bladerf *dev, bladerf_smb_mode mode)
API_EXPORT int CALL_CONV	bladerf_get_smb_mode (struct bladerf *dev, bladerf_smb_mode *mode)
API_EXPORT int CALL_CONV	bladerf_set_rational_smb_frequency (struct bladerf *dev, struct bladerf_rational_rate *rate, struct bladerf_rational_rate *actual)
API_EXPORT int CALL_CONV	bladerf_set_smb_frequency (struct bladerf *dev, uint32_t rate, uint32_t *actual)
API_EXPORT int CALL_CONV	bladerf_get_rational_smb_frequency (struct bladerf *dev, struct bladerf_rational_rate *rate)
API_EXPORT int CALL_CONV	bladerf_get_smb_frequency (struct bladerf *dev, unsigned int *rate)

Enumeration Type Documentation

bladerf_smb_mode

enum bladerf_smb_mode

SMB clock port mode of operation

Enumerator
BLADERF_SMB_MODE_INVALID	Invalid selection
BLADERF_SMB_MODE_DISABLED	Not in use. Device operates from its onboard clock and does not use J62.
BLADERF_SMB_MODE_OUTPUT	Device outputs a 38.4 MHz reference clock on J62. This may be used to drive another device that is configured with BLADERF_SMB_MODE_INPUT.
BLADERF_SMB_MODE_INPUT	Device configures J62 as an input and expects a 38.4 MHz reference to be available when this setting is applied.
BLADERF_SMB_MODE_UNAVAILBLE	SMB port is unavailable for use due to the underlying clock being used elsewhere (e.g., for an expansion board).

Definition at line 508 of file bladeRF1.h.

Macro Definition Documentation

BLADERF_SMB_FREQUENCY_MAX

#define BLADERF_SMB_FREQUENCY_MAX   200000000u

Maximum output frequency on SMB connector, if no expansion board attached.

Definition at line 497 of file bladeRF1.h.

BLADERF_SMB_FREQUENCY_MIN

#define BLADERF_SMB_FREQUENCY_MIN   ((38400000u * 66u) / (32 * 567))

Minimum output frequency on SMB connector, if no expansion board attached.

Definition at line 502 of file bladeRF1.h.

Function Documentation

bladerf_get_rational_smb_frequency()

API_EXPORT int CALL_CONV bladerf_get_rational_smb_frequency	(	struct bladerf *	dev,
		struct bladerf_rational_rate *	rate
	)

Read the SMB connector output frequency in rational Hz

Parameters

	dev	Device handle
[out]	rate	Pointer to returned rational frequency

Returns

0 on success, value from Error codes list upon failure

bladerf_get_smb_frequency()

API_EXPORT int CALL_CONV bladerf_get_smb_frequency	(	struct bladerf *	dev,
		unsigned int *	rate
	)

Read the SMB connector output frequency in Hz

Parameters

	dev	Device handle
[out]	rate	Pointer to returned frequency

Returns

0 on success, value from Error codes list upon failure

bladerf_get_smb_mode()

API_EXPORT int CALL_CONV bladerf_get_smb_mode	(	struct bladerf *	dev,
		bladerf_smb_mode *	mode
	)

Get the current mode of operation of the SMB clock port

Parameters

	dev	Device handle
[out]	mode	Desired mode

Returns

0 on success, or a value from Error codes list on failure.

bladerf_set_rational_smb_frequency()

API_EXPORT int CALL_CONV bladerf_set_rational_smb_frequency	(	struct bladerf *	dev,
		struct bladerf_rational_rate *	rate,
		struct bladerf_rational_rate *	actual
	)

Set the SMB clock port frequency in rational Hz

Parameters

	dev	Device handle
[in]	rate	Rational frequency
[out]	actual	If non-NULL, this is written with the actual

The frequency must be between BLADERF_SMB_FREQUENCY_MIN and BLADERF_SMB_FREQUENCY_MAX.

This function inherently configures the SMB clock port as an output. Do not call bladerf_set_smb_mode() with BLADERF_SMB_MODE_OUTPUT, as this will reset the output frequency to the 38.4 MHz reference.

Warning

This clock should not be set if an expansion board is connected.

Returns

0 on success, BLADERF_ERR_INVAL for an invalid frequency, or a value from Error codes list on failure.

bladerf_set_smb_frequency()

API_EXPORT int CALL_CONV bladerf_set_smb_frequency	(	struct bladerf *	dev,
		uint32_t	rate,
		uint32_t *	actual
	)

Set the SMB connector output frequency in Hz. Use bladerf_set_rational_smb_frequency() for more arbitrary values.

Parameters

	dev	Device handle
[in]	rate	Frequency
[out]	actual	If non-NULL. this is written with the actual frequency achieved.

This function inherently configures the SMB clock port as an output. Do not call bladerf_set_smb_mode() with BLADERF_SMB_MODE_OUTPUT, as this will reset the output frequency to the 38.4 MHz reference.

The frequency must be between BLADERF_SMB_FREQUENCY_MIN and BLADERF_SMB_FREQUENCY_MAX.

Warning

This clock should not be set if an expansion board is connected.

Returns

0 on success, BLADERF_ERR_INVAL for an invalid frequency, or a value from Error codes list on other failures

bladerf_set_smb_mode()

API_EXPORT int CALL_CONV bladerf_set_smb_mode	(	struct bladerf *	dev,
		bladerf_smb_mode	mode
	)

Set the current mode of operation of the SMB clock port

In a MIMO configuration, one "master" device should first be configured to output its reference clock to the slave devices via bladerf_set_smb_mode(dev, BLADERF_SMB_MODE_OUTPUT).

Next, all "slave" devices should be configured to use the reference clock provided on the SMB clock port (instead of using their on-board reference) via bladerf_set_smb_mode(dev, BLADERF_SMB_MODE_INPUT).

Parameters

	dev	Device handle
[in]	mode	Desired mode

Returns

0 on success, or a value from Error codes list on failure.