HD6417618 datasheet(345/646 Pages) RENESAS

345 / 646 page

Section 12 Ethernet Controller Direct Memory Access Controller (E-DMAC)

Rev. 6.00 Jun. 12, 2007 Page 313 of 610

REJ09B0131-0600

Notes: 1. The specified constant period is the timeout period mentioned in section 12.4.1, Usage Notes on SH-Ether EtherC/E-DMAC Status Register

(EESR).

2. Set n with reference to the maximum specified time values in table 12.2.

: Processing added as the countermeasure for the problem

Yes

Next transmission task

generated?

TACT = 0?

Yes

Prepare multiple transmit descriptors.

Transmission starts.

Transmission task

End

After setting the transmit descriptor,

set the TR bit in EDTRR to 1.

Read the TACT bit of the

corresponding transmit descriptor.

After setting the corresponding transmit

descriptor, set the TR bit in EDTRR to 1.

Call an OS service routine with

a timeout function to place the

transmission task in a waiting state.

Has the transmission task

left the waiting state within

he constant specified time?

i = 0;

Timeout

Read the TACT bit of the

corresponding transmit

descriptor.

i < n?

TACT = 0?

i++;

Yes

Interrupt handler

TC interrupt?

Interrupt other than TC?

Save EESR and clear the bit

by writing 1.

Generation of EtherC/E-DMAC

interrupt

End

Make an OS service call to bring the

transmission task out of the waiting state.

Interrupt processing for interrupts

other than TC

Issue a software reset to

initialize the EtherC and

E-DMAC modules.

Make initial settings of the

EtherC and E-DMAC modules.

Initialize the transmit/receive

descriptors and transmit/receive

buffers.

Figure 12.13 Countermeasure for the Case with TC Interrupt-Driven Software: Addition of

Timeout Processing within the Limit Imposed by the Maximum Specified Time

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