Photoionization Detector Module PIM CPN
User Manual
PIM_CPN - User Manual (en) - 1.08.docx
Analytical Control Instruments GmbH, Volmerstraße 9A, 12489 Berlin, Germany, www.aci-berlin.com
Page 34 of 48
11
I2C Communication
The communication is compatible with the I2C-Bus specification.
I2C signal level
VCC level
I2C SCL clock frequency
I2C standard mode up to 100 kHz
I2C slave address in decimal
32 ( default ) can be changed via UART command
USAGE
–
DO NOT USE UART AND I2C TOGETHER
The UART baudrate is selected by I2C lines levels at device startup.
Using UART and I2C together may result in wrong baudrate selection.
11.1
Data transfer
Reading data from module
S ADDR W A REG 0 A
…
REG 3 A Sr ADDR R A DATA 0 A
…
DATA N N P
Writing data to module
S ADDR W A REG 0 A
…
REG 3 A DATA 0 A
…
DATA N A P
Symbol description
from slave to master
S I2C START condition
from master to slave
A I2C ACK (acknowledge - SDA low)
N I2C NACK (not acknowledge - SDA high)
W
I2C write ( ‘0’ )
Sr I2C repeated START condition
R
I2C read ( ‘1’ )
P I2C STOP condition
ADDR I2C SLAVE ADDRESS ( 7 bit )
REG 0 … REG 3
Data Register to access ( 4 bytes )
DATA 0 … DATA N
Data bytes ( max 32 )