Utility Functions

Functions
void	edt_spi_send_packet (EdtDev edt_p, uint8_t *cmdbuf)
	Send a command packet to the msp430 via the SPI; wait for output fifo full but not ACK/NAK reply. More...
uint8_t	edt_spi_get_byte (EdtDev edt_p)
	Polls the EDT SPI master for a single byte. More...
uint8_t	edt_spi_put_byte (EdtDev edt_p, uint8_t ch)
	Sends one byte to the EDT SPI master. More...
void	edt_spi_flush_fifo (EdtDev edt_p)
	Flushes the EDT SPI input and output fifos, discarding all data. More...
char *	edt_spi_putstr (EdtDev edt_p, char *const str)
	Send a single line of ascii string to the msp430 over SPI. More...

Detailed Description

Utility Functions

Function Documentation

edt_spi_send_packet()

void edt_spi_send_packet	(	EdtDev	edt_p,
		uint8_t *	cmdbuf
	)

Send a command packet to the msp430 via the SPI; wait for output fifo full but not ACK/NAK reply.

After a packet-start byte is received, call this routine to input the packet and check the CRC.

Parameters

edt_p	The EDT open device handle.
str	The formatted command buffer to send as a packet.

Packets to and from the msp430 microcontroller over the SPI bus always start with

#define SPI_PKT_START 0x82 Start of packet byte.

followed by a command buffer, followed by a two-byte command buffer CRC check.

The command buffer consists of the following:

byte 0: Command byte byte 1: Number of data bytes 0 - 60 bytes 2 - 62: Command specific data bytes

Currently supported commands are:

#define SPI_PACKET_LOOP     0   Loop back packet; send back the packet.  Data size

0-60 bytes; no ACK/NAK response.

#define SPI_TIMECODE_EN     1   Enable (1) or disable (0) the 1 Hz ascii-hex

timestamp. Data size 1 byte. ACK/NAK response.

#define SPI_CLK_SELECT      2   Select msp430 clock source as internal DCO (0) or

external XIN (1) plus clock rate. ACK/NAK response. Data size 5 bytes; first byte selects internal/external, last 4 bytes is an integer specifying the clock rate in Hz; LS byte first; MS byte last. Currently supported clock rates for DCO (0) are 1, 8, 12 and 16 Mhz. Currently supported clock rate for XIN (1) is 10 Mhz.

#define SPI_TIMECODE_PKT    3   Sent from msp430 to FPGA.  Data consists of 4-8

bytes of timecode LSByte first, extended UNIX seconds time format.

The CRC check bytes apply to the command buffer (command, length and data bytes), and is computed as follows where CKL is the low CRC byte, CKH is the high CRC byte, B1 is the Command byte and Bn is the last data byte (derived from Texas Instruments Application Report SLAA089D "Features of the MSP430 Bootstrap Loader"):

CKL = INV [ B1 XOR B3 XOR ... XOR Bn–1 ]
CKH = INV [ B2 XOR B4 XOR ... XOR Bn ]

edt_spi_get_byte()

uint8_t edt_spi_get_byte

(

EdtDev

edt_p

)

Polls the EDT SPI master for a single byte.

Parameters

edt_p

The EDT open device handle.

Returns

The byte obtained from the SPI interface.

edt_spi_put_byte()

uint8_t edt_spi_put_byte	(	EdtDev	edt_p,
		uint8_t	ch
	)

Sends one byte to the EDT SPI master.

Parameters

edt_p	The EDT open device handle.
ch	The byte to send to the SPI master.

Returns

The byte sent to the SPI interface.

edt_spi_flush_fifo()

void edt_spi_flush_fifo

(

EdtDev

edt_p

)

Flushes the EDT SPI input and output fifos, discarding all data.

Parameters

edt_p

The EDT open device handle.

edt_spi_putstr()

char * edt_spi_putstr	(	EdtDev	edt_p,
		char *const	str
	)

Send a single line of ascii string to the msp430 over SPI.

Parameters

edt_p	The EDT open device handle.
str	The null-terminated string to send to the EDT SPI interface.

Returns

A pointer to the null-terminated argument string.