DS2282/87-22282-000 Maxim Integrated, DS2282/87-22282-000 Datasheet - Page 7

• Manufacturer Part Number: DS2282/87-22282-000
• Description: Network Controller & Processor ICs
• Manufacturer: Maxim Integrated

Specifications of DS2282/87-22282-000

• Supply Current (max): 30 mA
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• Package / Case: SIL-30
• Minimum Operating Temperature: 0 C
• Operating Supply Voltage: 5 V
• Part # Aliases: 90-22820-000

Address Byte
EB
A4
A3
A2
A1
A0
The second byte is also always written to the DS2282
and is called the Register Byte. The Register Byte con-
tains the address of the register that is to be either read
from or written to. The MSB in the Register Byte is the
Clear Bit. The Clear Bit is used to clear a register after it
has been read; hence, it can only be used in association
with read registers. Furthermore, only certain read reg-
isters are clearable. See Tables 1 and 2. Typically, the
only registers that can be cleared after reading are reg-
isters that count events and/or errors.
Register Byte
CB
A5
A4
A3
A2
A1
A0
The third through fifth bytes (third through 194th for five
of the 54016 registers) are the Data Bytes. The third
byte in the communication over the serial port may be
either read from or written to the DS2282. Bytes four
and five are always read from the DS2282 since there
are no write registers longer than one byte. When writ-
ing Data Bytes to the DS2282, the Extra Bit must be set
to zero and the Extra Bit will be set to zero by the
DS2282 for transfers at TXD.
(MSB)
(MSB)
EB
CB
0
0
0
Extra Bit. Should always be set to one.
Address Bit 4. The MSB of the serial port
address.
Address Bit 3.
Address Bit 2.
Address Bit 1.
Address Bit 0. The LSB of the serial port
address.
Clear Bit. Set to a one if register is to be
cleared after reading.
Address Bit 5. The MSB of the register
address.
Address Bit 4.
Address Bit 3.
Address Bit 2.
Address Bit 1.
Address Bit 0. The LSB of the register
address.
A5
0
A4
A4
A3
A3
A2
A2
A1
A1
(LSB)
(LSB)
A0
A0
Data is read from and written to the DS2282, least signif-
icant bit first. Also in multiple byte registers, the least
significant byte is read first and the most significant byte
is read last.
As an example, if a DS2282 had been programmed for a
serial port address of five (decimal) and the user wished
to retrieve and clear the count in the BPV Count Regis-
ter (BPVCR=09h), then the following transactions
would occur:
1. The Address Byte with the Extra Bit set to one and
2. The Register Byte with the Clear Bit set to one and
3. The current value in the 24–bit (3–byte) BPVCR is
4. The BPVCR will automatically be reset to zero after
The serial port communication on the DS2282 is han-
dled by the onboard DS5000 Soft Microcontroller. The
DS5000 is based on an 8051–type architecture. The
DS2282 utilizes the asynchronous Mode 2 operation of
an 8051–like microcontroller. Hence, each byte written
to the DS2282 must be preceded by a start bit (0) and
followed with a stop bit (1). See Figure 4. The DS2282
will append start and stop bits to the bytes that it trans-
mits back to an external controller via the TXD pin. More
information on Mode 2 operation can be found in the
DS5000 Soft Microcontroller User’s Guide.
REGISTER DESCRIPTION
There are five sets of registers in the DS2282: the Sta-
tus Register, the User Register, the Loopback Control
Register, the T1.403 Registers, and the 54016 Regis-
ters. See Tables 2 through 6. The Status Register (SR),
the User Register (UBR), and the Loopback Control
Register (LBCR) are always available for access. Ei-
ther the T1.403 register set or the 54016 register set will
be available depending on whether the DS2282 is pro-
grammed via the UBR to operate in either T1.403 or
54016 environments, respectively.
the proper serial port address <100000101> would
be written to the DS2282, least significant bit first.
the proper register address for the BPVCR selected
<100001001> would be written to the DS2282, least
significant bit first.
read from the DS2282; the least significant bit in the
least significant byte is read first and the most signifi-
cant bit in the most significant byte is read last.
the read is completed.
022798 7/22
DS2282