M66596FP datasheet(81/133 Pages) RENESAS

81 / 133 page

M66596FP/WG

rev .1.00

2006.3.14

page 79 of 127

3.4.1.6 Buffer memory operation (continuous transfer setting)

Either the continuous transfer mode or the non-continuous transfer mode can be selected, using the CNTMD

bit of the DCPCFG register and the PIPExCFG register. This selection is valid for pipes 0-5.

The continuous transfer mode function is a function that sends and receives multiple transactions in succession.

When the continuous transfer mode is set, data can be transferred without interrupts being issued to the CPU,

up to the buffer sizes assigned for each of the pipes.

In the continuous sending mode, the data being written is divided into packets of the maximum packet size

and sent. If the data being sent is less than the buffer size (short packet, or the integer multiple of the maximum

packet size is less than the buffer size), “BVAL=1” must be set after the data being sent has been written.

In the continuous reception mode, interrupts are not issued during reception of packets up to the buffer size,

until the transaction counter has ended, or until a short packet is received.

Figure 3.21 shows an example of buffer memory operation for the controller.

Max Packet Size

Not used area

CNTMD=0

When packet is received

Max Packet Size

CNTMD=1

When packet is received

Interrupt issued

Max Packet Size

Not used area

CNTMD=0

When packet is sent

Max Packet Size

CNTMD=1

When packet is sent

Sending enabled

Figure 3.21 Example of buffer memory operation

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