PM6344 datasheet(205/256 Pages) PMC

205 / 256 page

STANDARD PRODUCT

PMC-Sierra, Inc.

PM6344 EQUAD

PMC-951013

ISSUE 5

QUADRUPLE E1 FRAMER

192

13.1 Using the Internal FDL Transmitter

Upon reset of the EQUAD, the XFDL should be disabled by setting the EN bit in

the XFDL Configuration Register to logic 0. If data is not ready to be transmitted,

the TDLINT[x] output should also be masked by setting the INTE bit to logic 0.

When using the internal HDLC transmitter, the XFDL Configuration Register

should be initialized for transmission: if the FCS is desired, the CRC bit should be

set to logic 1; if the block is to be used in interrupt driven mode, interrupts should

be enabled by setting the INTE bit to logic 1. Finally, the XFDL can be enabled

by setting the EN bit to logic 1. If no message is sent after the EN bit is set to

logic 1, continuous flags will be sent.

The XFDL can be used in a polled, interrupt driven, or DMA-controlled mode for

the transfer of frame data. In the polled mode, the TDLINT[x] and TDLUDR[x]

outputs of the XFDL are not used, and the processor controlling the XFDL must

periodically read the XFDL Status Register to determine when to write to the

XFDL Transmit Data Register. In the interrupt driven mode, the processor

controlling the XFDL uses either the TDLINT[x] output, or the main processor

INTB output and the interrupt source registers, to determine when to write to the

XFDL Transmit Data Register. In the DMA controlled mode, the TDLINT[x] output

of the XFDL is used as a DMA request input to the DMA controller, and the

TDLUDR[x] output is used as an interrupt to the processor to allow handling of

exceptions. The TDLUDR[x] output can also be enabled to generate a processor

interrupt through the common INTB output via the TDLUDRE bit in the Datalink

Options register.

Polled Mode

If the XFDL data transfer is operating in the polled mode (TXDMASIG,

TFRACE1, TDLINTE, and TDLUDRE bits in the Datalink Options Register are set

to logic 0), then a timer periodically starts up a service routine, which should

PM6344 Datasheet(PDF) 205 Page - PMC-Sierra, Inc