Datasheet

DS_INLC10AQ Revision 1.0_B

Inova Semiconductors Confidential

Page 18 of 35

4.1.4 Bit Retransmission

To ensure a correct bit-timing, the forwarded data is regenerated with the clock of the device. The

retransmission starts with its own frame-sync when it can be guaranteed that a valid frame-sync timing can

be created. A new frequency synchronization is only created after the freq-sync on the reception side has

been received (the first four bits). Therefore, the minimum propagation delay tpd introduced by the

retransmission is four bit widths tBW.

Name

Description

Min.

Typ.

Max.

Unit

tpd

Propagation delay

2

4

5.2

µs

Table 15 - Propagation delay

To guarantee a correct bit-timing the device uses its own clock as reference and will never transmit faster

than its own bit-timing defines, but if the received freq-sync was slower, this timing is used for the

retransmission.

The retransmission uses a FIFO to compensate for speed differences between reception and transmission.

Due to the variance in the oscillator clocks of different devices, after each transmission a pause of 43% of

the nominal transmission time has to be introduced. If the transmission is created by a chip with ±30%

oscillator clock variation the time has to be increased to a total of 70% of the transmission duration.

4.1.5 Initialization

The digLED_Init_Strip command initializes a particular ISELED chain by issuing the command on an

associated ISELED communication channel.

This command is always the first command to be transmitted after power-up or reset. The command

initializes a chain of devices by assigning the address of the device and by en- or disabling the phaseshift,

the CRC and temperature compensation functions. The digLED_Init_Strip command is always executed

with a CRC checksum. This is true for both, the command and the response frame.

If any command is received by a device before initialization, the command is always considered as illegal

and the error status bit for an undefined command is set.

This may happen in the chain’s first device only,

as a non-initialized device does not forward received messages.

If the first device in the chain receives a digLED_Init_Strip command, it takes the received address as its

own device address and afterwards transmits another digLED_Init_Strip frame to the next device in the

chain. It increments the address before the transmission. As the adjacent devices proceed in the same

manner, the devices in the chain get enumerated with ascending addresses. When the final device in the

chain recognizes there is no receiving device at its downstream link, it transmits a response frame upstream.

The response frame to a digLED_Init_Strip command carries the configuration word read from the OTP. It

also transmits the own devices address just initialized.

All upstream devices wait for the responses to be received and forward them towards the microcontroller.