GS9001 データシートの表示（PDF） - Gennum -> Semtech

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GS9001

EDH Coprocessor

Gennum -> Semtech 

Error Reporting

Error reporting is meant to provide the information necessary 7.

to allow system diagnostics. There are fifteen error flags in

total, which are used to identify specific error types. All flags

are available to be read or overwritten via the I2C interface.

The definition of these flags and an explanation of how the

device handles these flags are described below.

UES for AP, FF and Ancillary

U E S i s s e t i f t h e i n c o m i n g U E S i s s e t . A l s o,

i f the incoming data does not have an error data

packet, this flag is set. This is to inform the down-

stream devices that the data being sent has not

been previously checked for data errors.

The acronyms used are:

In addition to error flag access through the I2C interface,

EDA Error Detected Already

selected EDH, EDA, IDH, IDA and UES flags are available on

two user programmable output pins. Table 2 (on page 3)

1.

2.

3.

4.

EDH Error Detected Here

IDH Internal device error Detected Here

IDA Internal device error Detected Already

D UES Unknown Error Status

E AP Active Picture

D FF Full Field

N S EDH for AP and FF

E N If the incoming CRC checkword is different from the

calculated CRC checkword, the EDH flag is set.

M IG EDH for Ancillary

If the checksum for the ancillary data does not match

M S the calculated checksum, this flag is set.

O E EDA for AP and FF

This flag is generated by summing the incoming

C D EDA flag with the product of the incoming EDH

flag and the valid CRC bit. As a result, if the

E incoming EDH flag is set and the EDA flag has not

R W been set, the EDH flag will be recoded to EDA and

then cleared. If the incoming CRC is invalid, then the

E outgoing EDA flag will be determined by the incoming

T EDA flag only. This is to support devices in the

N transmission path that do not generate valid CRC,yet

O pass only the EDA flags.

N R EDA for Ancillary

This flag is the sum of the in-coming EDH and EDA

FO flags for ancillary data.

shows these error flags and the corresponding input addresses.

These flags are available for applications where access to the

I2C interface via microcontroller is not possible or cost effective.

These flags give the user immediate warning of transmission

related errors either locally or from upstream equipment.

In situations where the upstream equipment does not support

EDH, a new error data packet is inserted in the data stream as

specified in RP165. In this case the UES flag is set for active

picture, full field and ancillary data. The EDH, EDA and IDA

flags are reset for active picture and full field. For ancillary

data, the EDH flag is still reported if there are any checksum

errors and the EDA and IDA flags are reset. This is done since

the checksums for ancillary data may still be valid without the

presence of an error data packet in the data stream.

Transmit vs Receive Modes

The preceding description refers to the device in Receive

mode. In Transmit mode, valid CRC-check words for active

picture and full field are inserted and all error flags are reset.

Flag Masking

Any of the fifteen error flags can be set/reset or made transparent

using the I2C interface. Transparent flags are updated on the

occurrence of data errors. Flag masking can be done only

when the device is in the receive mode. During transmit mode

all error flags are reset. The transmit mode would be used for

source equipment and equipment that modifies or processes

the data before re-serializing.

Programmable Interrupt

The interrupt output can be made sensitive to any specific or

5. IDH for AP, FF and Ancillary

all error flags. This function is programmed using the sensitivity

flags SANC, SFF and SAP as described in the section for I2C

These flags are set by the user through the I2C interface WRITE format.

serial interface. They can be used to indicate any

internal device errors in the vicinity of the device. Errored Field Counter

Examples could be local hardware errors such as

a RAM failure or a system diagnostics failure on power-

up.

This 21 bit counter can be used to count the number of fields

in which data errors occur. The same set of sensitivity flags

used for the programmable interrupt, also control the

6. IDA for AP, FF and Ancillary

incrementing of this counter. This counter can be made to

increment on the occurrence of any specific type of error flag

This flag is the sum of the incoming IDH and IDA flags in a field.

for AP, FF and ancillary data.

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