CIRCC datasheet(55/70 Pages) SMSC

55 / 70 page

FRAME ERRORS

A framing error is any bit-wide violation that

occurs during the payload portion of NEC

consumer

remote

control

message

frames.

Payload data in this protocol always follows the

leader code and includes the custom code and

data code fields as shown in Figure 5.

The Frame Error bit in the SCE Line Status

occurs.

The Frame Error bit will not be set if

framing errors occur when the FRAME bit in the

SCE Consumer IR Remote Control Register is

inactive (“0”).

The bit-wide violations that produce framing

errors are defined as the continuous presence of

carrier for more than two or more bit cells, or the

continuous absence of carrier for four or more bit

cells. Note: bit cells are determined by the SCE

CIR Bit Rate Divider register. For example; if the

Bit Rate Divider is programmed for the NEC

format shown in Figure 5 when the FRAME bit is

“1”, then the Frame Error bit will be set if carrier

is detected for 1.125ms or greater, or if no carrier

is detected for 2.25ms or greater.

Note: It is possible for the FIFO to be empty with

the Frame Error bit set at the end of an invalid

NEC remote control message frame because the

payload data in messages with framing errors will

either be ignored or passed to the FIFO

depending on the data pattern and the frequency

of violations.

CIRCC Datasheet(PDF) 55 Page - SMSC Corporation