EEWORLDEEWORLDEEWORLD

Part Number

Search

DS2490X

Description
Bus Controller, CMOS,
CategoryThe embedded processor and controller    Microcontrollers and processors   
File Size462KB,50 Pages
ManufacturerDALLAS
Websitehttp://www.dalsemi.com
Download Datasheet Parametric View All

DS2490X Overview

Bus Controller, CMOS,

DS2490X Parametric

Parameter NameAttribute value
Is it Rohs certified?incompatible
MakerDALLAS
Reach Compliance Codeunknown
JESD-609 codee0
Maximum operating temperature70 °C
Minimum operating temperature
Package body materialCERAMIC
Encapsulate equivalent codeFLIP CHIP
power supply3.3,5 V
Certification statusNot Qualified
technologyCMOS
Temperature levelCOMMERCIAL
Terminal surfaceTin/Lead (Sn/Pb)

DS2490X Preview

DS2490
USB to 1-Wire Bridge Chip
www.maxim-ic.com
FEATURES
§
§
§
§
§
§
§
§
§
§
Communicates at regular and overdrive 1-
Wire
®
speeds
Supports 12V EPROM programming and stiff
5V pullup for EEPROM, sensors, and crypto
iButton
®
Slew rate controlled 1-Wire timing and active
pullup to accommodate long 1-Wire network
lines and reduce radiation
Programmable 1-Wire timing and driver
characteristics accommodate a wide range of
1-Wire network configurations
Low- to high-level command types, including
macros, for generating 1-Wire communication
Crystal oscillator timebase provides precision
timed 1-Wire waveforms
High-speed 12Mbps Universal Serial Bus
(USB) interface
Integrated USB-compliant transceiver
Supports USB remote wake-up from a 1-Wire
device event to resume a suspended host
system
0
o
C to +70
o
C operating temperature range
PIN ASSIGNMENT
24-Pin SO
Top View
(300-mil)
PMOD
NC
NC
NC
VB
SUSO
D-
D+
NC
1-WIRE
NC
GND
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
VD
NC
NC
NC
XO
XI
NC
VPP
NC
NC
NC
NC
Flip-Chip Package, Top View
A4
B4
C4
D4
E4
F4
G4
NC
A3
NC
B3
SUSO\
C3
D-
GND
E3
NC
F3
NC
G3
4.4 mm
NC
A2
PMOD
B2
VB
C2
D+
E2
1W
F2
NC
G2
NC
A1
VDD
B1
NC
C1
D1
NC
E1
NC
F1
NC
G1
NC
NC
XO
XI
7.1 mm
VPP
NC
NC
ORDERING INFORMATION
PART NUMBER
DS2490S
DS2490S/T&R
DS2490X
PACKAGE DESCRIPTION
24-pin SO
Tape & Reel of DS2490S
Flip-Chip Package, Tape & Reel
DESCRIPTION
The DS2490 is a bridge chip that enables communication between a USB host system and a 1-Wire bus.
It provides regular, overdrive, and flexible 1-Wire communication speeds and a full-speed 12Mbps
connection to USB. USB vendor-specific commands defined in this specification are used to control the
DS2490 and communicate with attached 1-Wire devices. A functional block diagram of the DS2490 is
shown in Figure 1.
1 of 50
120401
DS2490
SIGNAL SUMMARY
Table 1
SIGNAL NAME
VD
VPP
VB
D+
D-
1-Wire
PMOD
TYPE
PWR
PWR
PWR
I/O
I/O
I/O
I
O
FUNCTION
Power supply input for digital and 1-Wire functions. Range: 5.0
±
10%
Power supply input for 1-Wire EPROM programming. Range:
12V
±
0.25V
Power supply input for USB functions. Range: 3.3V
±
10% supply
regulated from USB supplied VBUS.
USB data—non-inverted of differential data pair.
USB data—inverted signal of differential data pair.
1-Wire input/output.
Reserved for future use. Must be tied to GND.
Suspend Output—buffered USB suspend-state output from USB device
controller. When HIGH the USB is in an active non-suspended state,
when LOW the USB has entered a suspended state. This is an open drain
output and requires an external pullup.
Crystal input. Use a 12.0 MHz, fundamental-mode, parallel-resonant
crystal. A 12.0MHz CMOS clock source may also be used.
Crystal output. Connect to other side of crystal 1 if used.
Ground reference and ground return for 1-Wire bus.
No connect. For factory use or reserved, do not connect to these pins.
SUSO
XI
XO
GND
NC
I
O
PWR
RELATED DOCUMENTS
This specification uses terms from and references or complies with the
Universal Serial Bus Specification
v1.1,
which may be obtained from the USB Implementers Forum website: www.usb.org. The USB
specification is considered to be part of the DS2490 specification.
DOCUMENT ORGANIZATION
The remainder of this document is organized into the following major sections:
SECTION
OVERVIEW
1-WIRE I/F CONTROLLER
USB COMMUNICATION
SUMMARY
Device functional summary and application examples
Edge control and timing diagrams of 1-Wire signals
Configuration model, core and vendor-specific command
summaries
Commands used to configure 1-Wire interface operational
characteristics
Commands used to control 1-Wire communication
command processing
Commands used to communicate with an attached 1-Wire
device
Technique to obtain device status information
Transceiver connection requirements
Oscillator connection requirements
2 of 50
MODE COMMANDS
CONTROL COMMANDS
COMMUNICATION COMMANDS
DEVICE FEEDBACK
USB TRANSCEIVER
OSCILLATOR
DS2490
SECTION
SUSPEND OUTPUT
ELECTRICAL CHARACTERISTICS
APPLICATION INFORMATION
APPENDIX 1
APPENDIX 2
APPENDIX 3
APPENDIX 4
SUMMARY
SUSO signal operation and purpose
DC and AC specifications
HW application example
CONTROL COMMANDS—USB setup packet encoding
COMMUNICATION COMMANDS—USB setup packet
encoding
MODE COMMANDS—USB setup packet encoding
USB command and command type constant codes
OVERVIEW
The DS2490 directly interfaces a USB port to a 1-Wire bus. As shown in Figure 1, the DS2490
incorporates a USB physical interface, a USB device controller coupled with a 1-Wire-specific USB
function core, and a 1-Wire bus interface controller. The 1-Wire interface controller shapes the slopes of
the 1-Wire waveforms, applies programming pulses or strong pullup to 5V, and reads the 1-Wire bus
using a non-TTL threshold to maximize the noise margin for best performance on large 1-Wire Networks.
1-Wire waveform timing is accurately controlled with a crystal-based oscillator.
The DS2490 also supports USB remote wake-up which enables the DS2490-based USB peripheral to
send resume signaling to a suspended host system. If the remote wake-up function is enabled and the host
system is in a suspended state, a 1-Wire device attachment will cause the DS2490 to perform a host
system wake-up and allow the 1-Wire device to be serviced.
DS2490 FUNCTIONAL BLOCK DIAGRAM
Figure 1
SUSO
USB
DESC
ROM
1-WIRE
I/F
CONTROLLER
D+
D-
USB
XCVR
USB
DEVICE
CONTROLLER
USB
1-WIRE
FUNCTION
CORE
EP
FIFOS
1-WIRE
VB
PWR
CNTL
OSC
CLK
GEN
VD
XI
XO
GND
VPP
Typical application examples of the DS2490 are shown in Figure 2 (a to c). As shown in all the examples,
all host control and communication with the device is accomplished over a USB communication link. A
USB vendor-specific command set, as defined in this document, is used to select operational modes
(MODE COMMANDS), control command processing (CONTROL COMMANDS), and communicate
over the 1-Wire interface (COMMUNICATION COMMANDS). Shown in Figure 2, example (a) is a
DS2490-based USB peripheral application. The peripheral function is a USB to 1-Wire adapter and
provides both USB and 1-Wire I/O connections. In this example, the peripheral is attached to the USB
enabled host computer either directly at a root port or through a USB hub. The 1-Wire bus interface
3 of 50
DS2490
provided by the DS2490 supports all 1-Wire devices manufactured by Dallas Semiconductor as well as
the various 1-Wire bus topologies simple multi-drop to complex 1-Wire Network. Example (b) and (c) in
Figure 2 are variations of example (a) in which the DS2490 is embedded in the host computer or a USB
HUB.
DS2490 APPLICATION EXAMPLES
Figure 2
1-WIRE INTERFACE CONTROLLER
1-Wire communication commands sent to the DS2490 are ultimately processed by the 1-Wire interface
controller. One of the tasks of the interface controller is to actively shape the edges of the 1-Wire
communication waveforms. This speeds up the recharging of the 1-Wire bus (rising edges) and reduces
ringing of long lines (falling edges). The circuitry for shaping rising edges is always active. The slew rate
of falling edges is actively controlled only at flexible speed and requires the parameter for slew rate
control being different from its power-on default value. See the MODE COMMANDS section for
parameter control and power-on defaults.
All Rising Edges
The active pullup of the rising edges reduces the rise time on the 1-Wire bus significantly compared to a
simple resistive pullup. Figure 3 shows how the DS2490 is involved in shaping a rising edge.
4 of 50
DS2490
ACTIVE PULLUP
Figure 3
5V
V
IAPTO
t
APUOT
V
IAPO
0V
1-Wire bus
is discharged
t
1
t
2
t
3
The circuit operates as follows: At t
1,
the pulldown (induced by the DS2490 or a device on the bus) ends.
From this point on the 1-Wire bus is pulled high by the weak pullup current I
WEAKPU
provided by the
DS2490. The slope is determined by the load on the bus and the value of the pullup current. At t
2,
the
voltage crosses the threshold voltage V
IAPO
. Now, the DS2490 switches over from the weak pullup
current I
WEAKPU
to the higher current I
ACTPU
. As a consequence, the voltage on the bus now rises faster.
As the voltage on the bus crosses the threshold V
IAPTO
at t
3
, a timer is started. As long as this timer is on
(t
APUOT
), the I
ACTPU
current will continue to flow. After the timer is expired, the DS2490 will switch back
to the weak pullup current.
Falling Edges (DS2490-initiated)
Whenever the DS2490 begins pulling the 1-Wire bus low to initiate a time slot, for example, it first turns
off the weak pullup current I
WEAKPU
. Then, at regular and overdrive speed it will generate a falling edge at
a slew rate of typically 15 V/µs. This value is acceptable for short 1-Wire busses and adequate for
communication at overdrive speed. For 1-Wire networks of more than roughly 30m length, flexible speed
should always be used. One of the parameters that is adjustable at flexible speed is the slew rate of
DS2490-initiated falling edges. The effect of the slew rate control is shown in Figure 4.
SLEW RATE CONTROL
Figure 4
t
F
5V
Target for
long lines:
4 ± 0.5 µs
low slew rate
high slew rate
0.8 V
0V
1-Wire bus
is pulled up
t
1
weak pull-up ends,
pull-down begins
Extensive tests have shown that 1-Wire networks with lengths of up to 300m will perform best if the fall
time t
F
is in the range of 4 ± 0.5µs. This translates into a slew rate of approximately 1V/µs. This slew rate
is typically achieved by selecting a PULLDOWN SLEW RATE parameter code of 0 x 4 (see MODE
COMMANDS). If the actual measured fall time is longer than the target value, a parameter code of 0 x 3
5 of 50
EEWORLD University ---- OMAPL138/C6748/AM1808 system design
OMAPL138/C6748/AM1808 system design : https://training.eeworld.com.cn/course/474...
chenyy MCU
A universal CRC16 algorithm program + host computer software
As the title: [code]#define CRC_POLYNOM 0x8408 //CRC16 polynomial, tentatively use this u16 CRC_16(u8 length, u8 *checksource) { u8 verifyi,verifyj; u16 verifynum=0xffff; //verifynum is the initial va...
caizhiwei MCU
Ask two questions about 485, thank you!
1. What kind of cable should be used for 485 transmission line? I saw on the Internet that twisted pair cable is used. 2. For the 485 to 232 converter, is it that only sending and receiving at the 232...
yangxf1217 Microchip MCU
What does it take to be proficient in ARM?
Recently, I always feel that I am stagnant and not making progress. Can an expert give me some advice on what it means to be proficient in ARM? What specific aspects are involved?...
MD2010 Talking about work
Many colleagues resigned in August.
In August, many colleagues resigned from the company. Most of them had their registered residence in other places. I don’t know why. There must be a management problem!...
DIAG Talking about work
Does anyone know how to add a third-party component library to PROTEUS?
Does anyone know how to add a third-party component library to PROTEUS? I'm using version 7.5sp3. I added the .lib file to the component library, but the components are still the same as before. What'...
shinecl Embedded System

EEWorld
subscription
account

EEWorld
service
account

Automotive
development
circle

Robot
development
community

Index Files: 965  1050  389  604  1873  20  22  8  13  38 
Datasheet   0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Room 1530, 15th Floor, Building B, No. 18 Zhongguancun Street, Haidian District, Beijing Telephone: (010) 82350740 Postal Code: 100190
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved 京ICP证060456号 京ICP备10001474号-1 电信业务审批[2006]字第258号函 京公网安备 11010802033920号