ST7FDALI View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST7FDALI
STMicroelectronics
'ST7FDALI' PDF : 141 Pages View PDF
ST7DALI
DALI COMMUNICATION MODULE (Cont’d)
11.4.3 DALI Standard Protocol
The DALI protocol uses the bi-phase Manchester
asynchronous serial data format. All the bits of the
frame are bi-phase encoded except the two stop
bits.
■ The transmission rate is about 1.2 kHz. The bi-
phase bit period is 833.33 us ±10%.
■ A forward frame consists of 19 bi-phase
encoded bits:
– 1 start bit (0->1: logical ’1’)
– 1 address byte (8-bit address)
– 1 data byte (8-bit data)
– 2 high level stop bits (no change of phase)
■ A backward frame consists of 11 bi-phase
encoded bits:
– 1 start bit (0->1: logical ’1’)
– 1 data byte (8-bit data)
– 2 high level stop bits (no change of phase)
A forward frame consists of 19 bi-phase encoded
bits: 1 start bit (logical ’1’), 1 address byte and 1
data byte. The frame is terminated by 2 stop bits
(idle). The stop bits do not contain any change of
phase.
A backward frame consists of 11 bi-phase encod-
ed bits: 1 start bit (logical ’1’) and 1 data byte. The
frame is terminated by 2 stop bits (idle). The stop
bits do not contain any change of phase.
The transmission rate, expressed as a bandwidth,
is specified at 1.2 kHz for the forward channel and
for the backward channel.
The settling time between two subsequent forward
frames is 9.17 ms (minimum).
The settling time between forward and backward
frames is between 2.92 ms and 9.17 ms. If a back-
ward frame has not been started after 9.17 ms,
this is interpreted as "no answer".
In the event of code violation, the frame is ignored.
After a code violation has occurred, the system is
ready again for data reception.
Figure 42. DALI Standard Frame
FORWARD FRAME
start bit
address byte
data byte
stop bits
a7 a6 a5 a4 a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0
2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 2T 4T
BACKWARD FRAME
start bit
data byte
stop bits
d7 d6 d5 d4 d3 d2 d1 d0
2T 2T 2T 2T 2T 2T 2T 2T 2T 4T
Logical ’1’
BI-PHASE LEVELS
Logical ’0’
2T
2T
2T = 833.33 us ±10%
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