LDLL16ENTR datasheet(37/102 Pages) STMICROELECTRONICS

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5.6.2

Broadcast frame for current setting and PWM duty cycle setting

As shown in the Figure 24, a broadcast frame uses the ID starting with ‘1’ followed by three ‘1’s and the chain

number. Bit 6 “CUR” defines whether the data contains PWM duty cycle data (0) or current setting data (1). The

six-bit chain number allows the assignment of 64 chains with up to four responders consisting of 16-channel

entities each.

Figure 24. Broadcast frame

1 CUR

CTRL

CRC

ACK/EOF

CUR=0: Duty cycle update

16x8bit

CUR=1: Current setting update

Chain ID[5:0]

Position 00_Data_Ch0-Ch15

Position 01_Data_Ch0-Ch15

Position 10_Data_Ch0-Ch13

Position 11_Data_Ch0-Ch15

In each 16-byte data package data for Ch15, respectively the highest channel number, is the MSB, data for Ch0,

respectively the lowest channel number, is the LSB.

This broadcast frame is ignored by the responder as long as its reset bit RSTB is not cleared.

5.6.3

Chain initialization

A specific broadcast frame is sent to all responders to inform them about the chain they belong to and their

position within this chain, so each responder is able to grab data intended for it.

Figure 25. Broadcast chain initialization

0 CTRL

CRC

ACK/EOF

repeated up to 21 times

0, Chain ID [5:0], 0

000, Pos [1:0], 00, Responder ID [8]

Responder ID [7:0]

...

The ID for this chain initialization frame is "1_0110_0000000". For every responder three bytes are used to

identify the chain it belongs to, its position and the addressed responder with the following data structure for each

responder:

•

MSB: 0, chain ID[5:0], 0

•

Next byte: 000, Pos[1:0], 00, responder ID[8]

•

LSB: responder ID[7:0]

•

Position 00: responder picks data bytes 0-15

•

Position 01: responder picks data bytes 16-31

•

Position 10: responder picks data bytes 32-47

•

Position 11: responder picks data bytes 48-63

Note:

If a device has several responder IDs (that is a 32-channel device has two responder IDs), those responder IDs

must be assigned to different chain IDs.

Responder IDs of the same device cannot be initialized in a single broadcast frame.

As reported in Figure 34, it is possible to initialize up to 21 responders within one chain initialization broadcast

frame.

Chain initialization is executed on the responder, even if its reset bit RSTB is set. Chain initialization does not

clear reset bit RSTB.

5.6.4

Go to sleep/wake up pattern

For sending the network to sleep and waking it up again a dedicated ID is defined.

The reserved WUP ID is "1_000_011_1100". A frame with this ID and without data (DLC = 0) is the command to

send all responders into sleep/standby mode. This is shown in the Figure 26.

Figure 26. Send-To-Sleep command

"1_000_011_1100"

CTRL

CRC

ACK/EOF

For waking up all the responders, in the network the data in the payload satisfy the wake-up pattern requirements

of ISO11898-2 with tCAN_FILTER (short) at 1 Mb/s.

This wake up pattern is repeated in the eight data bytes of the frame shown in the Table 10. The responders

recognize the dominant-recessive-dominant pulse in which the three individual pulses are longer than the

specified filter time. These pulses are contained in the data field.

LDLL16EN

Communication interface

DS14111 - Rev 5

page 37/102

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