SLRC400 Datasheet, PDF (102/130 Pages) NXP Semiconductors – I·CODE Reader IC

Philips Semiconductors
I•CODE Reader IC
Product Specification Rev. 2.0 November 2001
SL RC400
16.4.2.4 Communication Errors
The following table shows which event causes the setting of error flags:
Cause
Received data did not start with a SOF pattern.
The CRC block is not equal the expected value.
The received data is shorter than the CRC block.
A collision is detected.
Table 16-3: Communication Error Table
Bit, that is set
FramingErr
CRCErr
CRCErr
CollErr
16.4.3 TRANSCEIVE COMMAND 1E_HEX
Command Code_hex
Action
Transceive
1E Transmits data from FIFO buffer to the label
and then activates automatically the receiver
Arguments and Data
Data Stream
Returned Data
Data Stream
The Transceive-Command first executes the Transmit-Command (see 16.4.1) and then automatically starts
the Receive-Command (see 16.4.2). All data that shall be transmitted is forwarded via the FIFO buffer and all
data received is returned via the FIFO buffer. The Transceive-Command can be started only by the
µ-Processor.
Note: To adjust the timing relation between transmitting and receiving, the RxWait Register is used to define
the time delay from the last bit transmitted until the receiver is activated. Furthermore, the BitPhase Register
determines the phase-shift between the transmitter and the receiver clock.
16.4.4 STATES OF THE LABEL COMMUNICATION
The actual state of the transmitter and receiver state machine can be fetched from ModemState in the
PrimaryStatus Register.
The assignment of ModemState to the internal action is shown in the following table:
ModemState
000
001
010
011
100
101
110
111
Name of State
Idle
TxSOF
TxData
TxEOF
GoToRx1
GoToRx2
PrepareRx
AwaitingRx
Receiving
Description
Neither the transmitter nor the receiver is in operation,
since none of them is started or the transmitter has not got input data
Transmitting the ‘Start Of Frame’ Pattern
Transmitting data from the FIFO buffer (or redundancy check bits)
Transmitting the ‘End Of Frame’ Pattern
Intermediate state passed, when receiver starts
Intermediate state passed, when receiver finishes
Waiting until the time period selected in the RxWait Register has expired
Receiver activated; Awaiting an input signal at pin Rx
Receiving data
Table 16-4: Meaning of ModemState
102
Preliminary