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Chapter 10. General Programmable Interface (GPIF) Page 10-41

Figure 10-23. Initialization Code for Single-Write Transactions

10.4.3 FIFO-Read and FIFO-Write Transactions

FIFO-Read and FIFO-Write waveforms transfer data to and from the FX2’s Slave FIFOs (see

Chapter 9 "Slave FIFOs"

). The waveform is started by writing to EPxTRIG, where “x” represents

the FIFO (2, 4, 6, or 8) to/from which data should be transferred, or to GPIFTRIG.

A FIFO-Read or FIFO-Write waveform will generally transfer a long stream of data rather than a

single byte or word. Usually, the waveform is programmed to terminate when a FIFO flag asserts

(e.g., when an IN FIFO is full or an OUT FIFO is empty) or after a specified number of

transactions

A “transaction” is a transfer of a single byte (if WORDWIDE = 0) or word (if WORDWIDE = 1) to or

from a FIFO. Using the

GPIFTool

’s terminology, a transaction is either an “Active” or “Next Data”.

10.4.3.1 Transaction Counter

To use the Transaction Counter for FIFO “x”, load GPIFTCB3:0 with the desired number of transac-

tions (1 to 4,294,967,295; 0 = 4,294,967,296). When a FIFO-Read or -Write waveform is triggered

on that FIFO, the GPIF will transfer the specified number of bytes (or words, if WORDWIDE = 1)

automatically.

This mode of operation is called

Long Transfer Mode

; when the Transaction Counter is used in this

way, the Waveform Descriptor should branch to the Idle State after each transaction.

void TD_Init( void )

{

… … … … …

GpifInit(); // Configures GPIF from GPIFTool generated waveform data

// TODO: configure other endpoints, etc. here

// TODO: arm OUT buffer(s) here

// setup INT4 as internal source for GPIF interrupts

// using INT4CLR (SFR), automatically enabled

//INTSETUP |= 0x03; //Enable INT4 Autovectoring

//SYNCDELAY;

//GPIFIE = 0x03; // Enable GPIFDONE and GPIFWF interrupt(s)

//SYNCDELAY;

//EIE |= 0x04; // Enable INT4 ISR, EIE.2(EIEX4)=1

// TODO: configure GPIF interrupt(s) to meet your needs here

… … … … …

// tell peripheral we’re going into high speed xfr mode

Peripheral_SetAddress( PERIPHCS );

Peripheral_SingleByteWrite( P_HSMODE );

}

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