Cherry 8x16 keyboard matrix driver. More...

Macros
#define	CHERRY8x16_MAX_NUM_OF_PRESSED_KEYS 6
	Maximum number of pressed keys kept in buffers.

#define	CHERRY8x16_DEFAULT_KEY_LOOKUP_MATRIX (const uint8_t*)0
	If passed to cherry8x16_init, default lookup matrix will be used.

#define	KEY_PACKET_MODIFIER_KEY_INDEX (0)
	Index in the key packet where modifier keys such as ALT and Control are stored.

#define	KEY_PACKET_RESERVED_INDEX (1)
	Index in the key packet where OEMs can store information.

#define	KEY_PACKET_KEY_INDEX (2)
	Start index in the key packet where pressed keys are stored.

#define	KEY_PACKET_MAX_KEYS (6)
	Maximum number of keys that can be stored into the key packet.

#define	KEY_PACKET_SIZE (KEY_PACKET_KEY_INDEX+KEY_PACKET_MAX_KEYS)
	Total size of the key packet in bytes.

#define	KEY_PACKET_NO_KEY (0)
	Value to be stored to key index to indicate no key is pressed.

Enumerations
enum	cherry8x16_status_t { CHERRY8x16_OK, CHERRY8x16_NOT_DETECTED, CHERRY8x16_INVALID_PARAMETER }

Functions
cherry8x16_status_t	cherry8x16_init (const uint8_t volatile row_port, uint16_t column_port, const uint8_t *key_lookup_matrix)
	Function for initializing the driver. More...

bool	cherry8x16_new_packet (const uint8_t *p_key_packet, uint8_t p_key_packet_size)
	Function for creating a new key packet if new data is available and key ghosting is not detected. More...

Detailed Description

Cherry 8x16 keyboard matrix driver.

Enumeration Type Documentation

Describes return values for: cherry8x16_init

Enumerator
CHERRY8x16_OK	Operation was succesful.
CHERRY8x16_NOT_DETECTED	Product/Revision ID was not what was expected
CHERRY8x16_INVALID_PARAMETER	Given parameters were not valid

cherry8x16_status_t cherry8x16_init	(	const uint8_t volatile *	row_port,
		uint16_t *	column_port,
		const uint8_t *	key_lookup_matrix
	)

Function for initializing the driver.

Note: Before calling this function, setup row_port as IO inputs with pulldowns enabled and column_port as IO outputs.

Parameters

row_port	Pointer to GPIO port address that is used as key matrix row input.
column_port	Pointer to GPIO port address that is used as key matrix column output.
key_lookup_matrix	If NULL, use a default key lookup matrix. Otherwise pointer to a 128 (8x16) element array containing HID keycodes.

Return values

CHERRY8X16_OK	Peripheral was initialized succesfully.
CHERRY8X16_NOT_DETECTED	Could not detect the peripheral.

Function for creating a new key packet if new data is available and key ghosting is not detected.

Parameters

p_key_packet	Array that will hold the created key packet. Previously created packet will be discarded.
p_key_packet_size	Key packet size in bytes.

Return values

true	If new packet was created.
false	If packet was not created.