PM8313 datasheet(159/192 Pages) PMC

159 / 192 page

PM8313 D3MX

DATA SHEET

PMC-920702

ISSUE 5

M13 MULTIPLEXER

149

Figure 10

- XFDL Underrun Sequence

Flag

TDLINT

D1 D2

TDLUDR

Abort

UDR

D1 D2

D[7:0]

INTE

Serial Data

inserted into

Datalink

This diagram shows the relationship between XFDL inputs and outputs in the

case of an underrun error. An underrun error occurs if the XFDL finishes

transmitting the current message byte before the processor writes the next byte

into the Transmit Data Register; that is, the processor fails to write data to the

XFDL in time. In this example, data is not written to the XFDL within five rising

clock edges after TDLINT is asserted at the beginning of the transmission of byte

D3. The TDLUDR interrupt becomes active at this point, and an abort, followed

by a flag, is sent out on the data link. Meanwhile, the processor must clear the

TDLUDR interrupt by setting the UDR bit in the Status Register to logic 0. The

TDLINT interrupt should also be disabled at this time by setting the INTE bit in

the Configuration/Control Register to logic 0. The data frame can then be

restarted as usual, by setting the INTE bit logic to 1. Transmission of the frame

then proceeds normally.

PM8313 Datasheet(PDF) 159 Page - PMC-Sierra, Inc