PCF8591
NXP Semiconductors
8-bit A/D and D/A converter
Eight different I2C-bus slave addresses can be used to address the PCF8591 (see
Table 5).
Table 5.
I2C slave address byte
Slave address
Bit
7
6
5
4
3
2
1
0
MSB
LSB
R/W
slave address
1
0
0
1
A2
A1
A0
The least significant bit of the slave address byte is bit R/W (see Table 6).
Table 6.
R/W-bit description
R/W
0
Description
write data
read data
1
Bit 1 to bit 3 of the slave address are defined by connecting the input pins A0 to A2 to
either VSS (logic 0) or VDD (logic 1). Therefore, eight instances of PCF8591 can be
distinguished on the same I2C-bus.
acknowledge
acknowledge
acknowledge
from PCF8591
from PCF8591
from PCF8591
S
ADDRESS
0
A
CONTROL BYTE
A
DATA BYTE
A
P/S
N = 0 to M
data bytes
mbl833
Fig 15. Bus protocol for write mode, D/A conversion
acknowledge
acknowledge
no acknowledge
from PCF8591
from master
S
ADDRESS
1
A
DATA BYTE
A
LAST DATA BYTE
1
P
N = 0 to M
data bytes
mbl834
Fig 16. Bus protocol for read mode, A/D conversion
PCF8591
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© NXP B.V. 2013. All rights reserved.
Product data sheet
Rev. 7 — 27 June 2013
13 of 31
NXP [ NXP ]
