LNBP21 STMicroelectronics, LNBP21 Datasheet - Page 7

• Manufacturer Part Number: LNBP21
• Description: LNBP SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND I2C INTERFACE
• Manufacturer: STMicroelectronics

LNBP1 SOFTWARE DESCRIPTION
INTERFACE PROTOCOL
The interface protocol comprises:
- A start condition (S)
ACK= Acknowledge
S= Start
P= Stop
R/W= Read/Write
SYSTEM REGISTER (SR, 1 BYTE)
R,W= read and write bit
R= Read-only bit
All bits reset to 0 at Power-On
TRANSMITTED DATA (I
When the R/W bit in the chip address is set to 0,
the main µP can write on the System Register
(SR) of the LNBP21 via I
X= don't care.
Values are typical unless otherwise specified
RECEIVED DATA (I
The LNBP21 can provide to the Master a copy of
the SYSTEM REGISTER information via I
in read mode. The read mode is Master activated
by sending the chip address with R/W bit set to 1.
At the following master generated clocks bits, the
LNBP21 issues a byte on the SDA data bus line
(MSB transmitted first).
At the ninth clock bit the MCU master can:
PCL
S
X
0
1
R, W
MSB
PCL
MSB
0
ISEL
X
0
1
0
TEN
0
1
X
R, W
ISEL
0
CHIP ADDRESS
2
LLC VSEL
C bus READ MODE)
X
0
0
1
1
1
2
2
C bus. Only 6 bits out of
C BUS WRITE MODE)
0
X
0
1
0
1
R, W
TEN
0
EN
1
1
1
1
1
1
1
1
1
1
0
0
OTF
X
X
X
X
X
X
X
X
X
X
X
LSB
R/W ACK
2
R, W
C bus
LLC
OLF
X
X
X
X
X
X
X
X
X
X
X
V
V
V
V
22KHz tone is controlled by DSQIN pin
22KHz tone is ON, DSQIN pin disabled
I
I
Pulsed (dynamic) current limiting is selected
Static current limiting is selected
Power blocks disabled, Loopthrough switch closed
OUT(min)
OUT(min)
MSB
OUT
OUT
OUT
OUT
- A chip address byte = hex 10 / 11 (the LSB bit
determines read(=1)/write(=0) transmission)
- A sequence of data (1 byte + acknowledge)
- A stop condition (P)
the 8 available can be written by the µP, since the
remaining 2 are left to the diagnostic flags, and are
read-only.
- acknowledge the reception, starting in this way
the transmission of another byte from the
LNBP21;
- no acknowledge, stopping the read mode
communication.
While the whole register is read back by the µP,
only the two read-only bits OLF and OTF convey
diagnostic informations about the LNBP21.
VSEL
R, W
=13V, V
=18V, V
=14V, V
=19V, V
=500mA, I
=400mA, I
UP
UP
UP
UP
=16V Loopthrough switch open
=21V Loopthrough switch open
=17V Loopthrough switch open
=22V Loopthrough switch open
OUT(max)
OUT(max)
R, W
EN
DATA
Function
=650mA I
=550mA I
OTF
R
SC
SC
=300mA
=300mA
LSB
ACK
LNBP21
OLF
LSB
R
7/24
P