DS3900K# Maxim Integrated Products, DS3900K# Datasheet - Page 7

• Manufacturer Part Number: DS3900K#
• Description: Power Management Modules & Development Tools 2-WIRE BUS INTERFACE NTERFACE EV KIT ROHS
• Manufacturer: Maxim Integrated Products

Specifications of DS3900K#

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Example: Sending the byte sequence {0x82, 0x20,
0x45, 0x67, 0x89} to DS3900 causes it to:
1.
2.
3.
4.
5.
6.
7.
8.
The Packet Read command allows up to 16 data bytes
to be read with a single 2-byte instruction. The read
operation will be sent to the device operating at the
device address set using the Set Packet Device
Address command. The first byte sent for a Packet
Read command is 0x9%, where % is one less than the
number of bytes to read (e.g. 0x95 reads 6 bytes). The
second byte sent determines the memory address to
begin reading from within the device that is being
addressed. After the second byte is received, the
DS3900 will begin a dummy write cycle that will
address the part as if writing, and write out the device
Table 4. Example of Writing to a DS1803
SEQ #
1
2
3
4
5
6
Send a 2-wire Start condition.
Write the device address
using Set Packet Device Address).
Write the memory address (0x20).
Write data 0x45 (to address 0x20).
Write data 0x67 (to address 0x21).
Write data 0x89 (to address 0x22).
Send a 2-wire Stop condition.
If the 2-wire device acknowledges all bytes of the
data transmission, the DS3900 will return (0x82);
otherwise it will return an error code (0xFA).
1ST BYTE SENT
0xA0
0xA1
0xA1
0xA1
0xA1
0xA3
SEND START COMMAND, WRITE 0x23 TO POT 0, AND 0X34 TO POT 1, SEND STOP COMMAND
2ND BYTE SENT
Place holder
Place holder
R/W =0 (previously set
0x00
0x50
0xA9
0x23
0x34
0x00
Data
Data
Data
Data
_____________________________________________________________________
Serial Communications Module
1ST BYTE RETURNED 2ND BYTE RETURNED
Command ack
Command ack
Command ack
Command ack
Command ack
Command ack
0xB0
0xB1
0xB1
0xB1
0xB1
0xB3
address followed by the memory address. Then a
restart condition is generated, and the device's read
address is sent to start the read operation. The DS3900
will begin reading the data from the 2-wire part and
sending it back to the PC. The DS3900 will acknowl-
edge all but the last data byte sent from the 2-wire part.
The last byte is Not Acknowledged, which is a standard
2-wire practice. Once it has read %+1 data bytes and
sent them to the PC, the DS3900 will send 0x9% if the
read occurred without error, or 0xFA if a problem did
occur.
Example: Sending the byte sequence {0x91, 0x20} to
the DS3900 will cause it to:
1.
2.
3.
4.
5.
6.
7.
Send a 2-wire Start command.
Write the device address R/W =0 (set previously
using Set Packet Device Address).
Write the memory address 0x20.
Send a 2-wire Start command (repeated-start).
Write the device address R/W =1 (set previously
using Set Packet Device Address).
Read the data (at address 0x20), send 2-wire
Acknowledge on 9th clock cycle, and send the
data read back to the PC.
Read the data (at address 0x21), send 2-wire Not
Acknowledge on 9th clock cycle, and send the
data read back to the PC.
For Evaluation Kits
None
None
None
None
None
None
2-wire start
Send 0x50 over
2-wire bus
(send write DS1803 addr)
Send 0xA9 over
2-wire bus
(write pot 0 command)
Send 0x23 over
2-wire bus
(write 0x23 to pot 0)
Send 0x34 over
2-wire bus
(write 0x23 to pot 1)
2-wire stop
DESCRIPTION
7