DS2490Y Maxim Integrated Products, DS2490Y Datasheet
DS2490Y
Specifications of DS2490Y
Related parts for DS2490Y
DS2490Y Summary of contents
Page 1
... 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-Wire and iButton are registered trademarks of Maxim Integrated Products, Inc. ® PIN-PACKAGE o ...
Page 2
SIGNAL SUMMARY Table 1 SIGNAL NAME TYPE VD PWR VD2 PWR VB PWR D+ I/O D- I/O 1-Wire I/O PMOD I O SUSO GND PWR NC RELATED DOCUMENTS This specification uses terms from and references or ...
Page 3
SECTION ELECTRICAL CHARACTERISTICS APPLICATION INFORMATION APPENDIX 1 APPENDIX 2 APPENDIX 3 APPENDIX 4 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 ...
Page 4
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 ...
Page 5
ACTIVE PULLUP Figure 3 The circuit operates as follows From this point on the 1-Wire bus is pulled high by the weak pullup current I DS2490. The slope is determined by the load on the bus and the ...
Page 6
If the fall time is shorter, a parameter code of 0x5 or higher should be used. Once determined, the value code for the PULLDOWN SLEW RATE control parameter should be stored in the host and ...
Page 7
DS2490 will then wait for t FILL command bits PST, NTF, and ICP, generate a command response byte that is available to the host. If the test for interrupt or short reveals a logic 0, the DS2490 will wait for ...
Page 8
WRITE 1 AND READ DATA TIME SLOT Figure 6 SPEED REGULAR OVERDRIVE FLEXIBLE* *Powerup defaults for Flexible speed: t WRITE 0 TIME SLOT Figure 7 SPEED REGULAR OVERDRIVE FLEXIBLE* *Powerup defaults for Flexible speed: t NOMINAL TIMING VALUES t t ...
Page 9
Pulse Wave Forms The PULSE COMMUNICATION COMMAND can be used to generate a strong pullup to 5V. The duration of the pulses is specified with the STRONG PULLUP DURATION mode register. Figure 8 shows timing of the pulse. For predefined ...
Page 10
USB CONFIGURATION Figure 9 USB HOST SYSTEM SW 1-WIRE CLIENT Endpoint (EP) Summary Description EP0 is the endpoint for the bi-directional default control pipe used for the USB enumeration process, USB core request communication, and all DS2490 specific ...
Page 11
Interface Alternate Setting Summary Table 2 EP1 Alt Setting poll interval 0 10ms 1 10ms 2 1ms 3 1ms Endpoint Feature Summary Table 3 Endpoint Transaction # Type 0 CONTROL 1 INTERRUPT 2 BULK 3 BULK 1. Direction in ...
Page 12
Notes: 1. The only valid configuration values are 0 and 1 for the SET_CONFIGURATION request. Configuration value 0 corresponds to the non-configured state. 2. Only the DEVICE and GET_DESCRIPTOR request. 3. Interface 0 is the only valid interface value for ...
Page 13
Command Type Description CONTROL_CMD 1-Wire interface control commands COMM_CMD 1-Wire interface communication commands MODE_CMD 1-Wire interface operational mode commands The 2-byte wValue field is encoded with the specific command. For Control and Mode commands, the field value corresponds to a ...
Page 14
As listed in Table 5 and summarized previously, there are eight Mode commands. The USB control transfer setup packet coding to transmit these commands is detailed in Appendix 3. Mode commands are immediately processed by the DS2490 when they are ...
Page 15
STRONG PULLUP DURATION—This command is used to set the time duration of a 1-Wire strong pullup. As shown in Table 7, the time is controlled with an unsigned 8-bit binary number between 0x00 and 0xFE which specifies the duration in ...
Page 16
Flexible Speed Write-1 Low Time Codes Table 9 Code Nominal Write-1 Low Time 0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8..0xF DSOW0 RECOVERY TIME—This command is used to select the Data Sample Offset (t recovery (t ) time (DSO/W0R) ...
Page 17
Power-On Default Modes Table 11 Setting/Parameter Strong pullup to 5V Dynamic Speed Change 1-Wire Bus Communication Speed +5V Strong Pullup Duration Pulldown Slew Rate Control Write-1 Low Time Data Sample Offset / Write-0 Recovery Time CONTROL COMMANDS DS2490 Control ...
Page 18
Control Command Set Descriptions: RESET DEVICE—This command performs a hardware reset equivalent to the power-on reset. This includes clearing all endpoint buffers and loading the Mode control registers with their default values. START EXECUTION—This command starts execution of Communication commands. ...
Page 19
COMMUNICATION COMMANDS Communication commands are used to communicate with and control an attached 1-Wire device(s). There are 14 Communication commands as summarized in Table 13. Communication commands also contain embedded command bits for conditional control or additional functionality. Appendix 2 ...
Page 20
Communication Command Set Descriptions: SET DURATION—This command changes the State Register pulse duration value for the strong pullup. The new duration value is loaded into the duration register as detailed in Appendix 2. The duration value can alternatively be changed ...
Page 21
RESET—This command is used to generate a reset pulse on the 1-Wire bus and to optionally change the 1-Wire speed. The new speed will take effect only if the embedded command bit SE is set to 1. When the ...
Page 22
Command parameters: EP2 data: EP3 data: If ICP = 0: 1 byte If ICP = 1: None Result Register: BLOCK I/O—This command accomplishes a direct 1-Wire write or read with optional strong pullup after the last byte of the block. ...
Page 23
Command parameters: EP2 data: EP3 data: Result Register: READ STRAIGHT—This command transmits a user-specified preamble of data to the 1-Wire bus and then reads back as many bytes as specified. The preamble typically consists of a 1-Wire command code followed ...
Page 24
FIFO content status must be monitored by host SW so that additional data can be sent to the FIFO when necessary. A similar EP3 FIFO content monitoring requirement exists for the block read. During a block read the number ...
Page 25
Command parameters: EP2 data: EP3 data: Result Register: WRITE SRAM PAGE—This command is used to write data to the scratchpad of an SRAM device and optionally check the CRC. To copy the data to its final memory location ...
Page 26
READ CRC PROT PAGE—This command is used to read one or multiple CRC-protected pages of EPROM devices and to read tamper-detect bytes and counter value of Monetary iButtons. If embedded command bit the CRC16 generator is selected; ...
Page 27
Command parameters: EP2 data: EP3 data page is not redirected and page is redirected: Result Register: SEARCH ACCESS—The SEARCH ACCESS command is used to either access a device using the Search ...
Page 28
Command parameters: EP2 data: EP3 data None Varies, blocks Result Register: 2 bytes: 1 byte 1-Wire command (Search ROM or Conditional Search ROM), 1 byte for number of devices. The number of ...
Page 29
DEVICE FEEDBACK DS2490 state and result feedback are provided to the host over the EP1 interrupt pipe. The host interrupt polling period for EP1 transfers is controlled by the alternate setting of the 1-Wire USB Interface as described in the ...
Page 30
Description Offset Write-1 Low Time 0x05 Data Sample Offset / 0x06 Write-0 Recovery Time Reserved (Test Register) 0x07 Device Status Flags 0x08 Communication 0x09 Command, Byte 1 Communication 0x0A Command, Byte 2 Communication 0x0B Command Buffer Status 1-Wire Data Out ...
Page 31
DS2490 RESULT REGISTERS Table 17 1,2 Offset 0x10 0x11 … 0x1F Notes: 1. Since Result Registers follow State Registers for interrupt transfers, the register offset starting value shown in Table 17 for Result Registers follows the last value of Table ...
Page 32
Data Value Description USB TRANSCEIVER Integrated within the DS2490 is a USB-compliant bus transceiver. To comply with USB cable termination requirements, resistors external to the DS2490 must be installed as shown in Figure 10. The 24, 1% tolerance resistors are ...
Page 33
SUSPEND OUTPUT Suspend output signal ( SUSO (configured or unconfigured) and the USB suspend state. A truth table for signal operation is listed in Table 19. This signal could be used stand-alone or combined with other external signals to power ...
Page 34
ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Range Storage Temperature Range Soldering Temperature • This is a stress rating only and functional operation of the device at these or any other conditions above those indicated ...
Page 35
NOTES: 1. Voltage difference between VD and 1-WIRE. 2. Applies for both unconfigured and configured USB states. 3. Applies for the USB suspend state. 4. Voltage referenced to ground AC CHARACTERISTICS CONDITIONS: PARAMETER USB I/F 1-Wire I/F CAPACITANCE CONDITIONS: PARAMETER ...
Page 36
HW DESIGN EXAMPLE: USB TO 1-WIRE ADAPTER Figure EMI Filter 1 VBUS GND 5 1.0 SHIELD L2 USB EMI Filter Notes: 1. Resistors are 1/8W, 5% unless noted. ...
Page 37
APPENDIX 1: DS2490 CONTROL COMMANDS, SETUP PACKET ENCODING CONTROL COMMANDS RESET DEVICE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength START EXECUTION Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength RESUME EXECUTION Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength ...
Page 38
CONTROL COMMANDS HALT EXECUTION WHEN DONE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength FLUSH COMM CMDS Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength FLUSH DATA RCV BUFFER Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength FLUSH DATA XMT ...
Page 39
CONTROL COMMANDS GET COMM CMDS Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength APPENDIX 2: DS2490 COMMUNICATION COMMANDS, EMBEDDED COMMAND BITS, SETUP PACKET ENCODING. Communication commands contain embedded command parameter bits in the wValue field. The definitions of bit parameters ...
Page 40
BIT NAME DESCRIPTION PST PST = 1 continuously generate 1-Wire Reset sequences until a presence pulse is discovered. PST = 0 generate only one 1-Wire Reset sequence performs a read function performs a ...
Page 41
COMMUNICATION COMMANDS PULSE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength 1-WIRE RESET Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength BIT I/O Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength 0x40 COMM_CMD byte 2 byte ...
Page 42
COMMUNICATION COMMANDS BYTE I/O Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength BLOCK I/O Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength 0x40 COMM_CMD byte 2 byte byte byte 2 byte 2 ...
Page 43
COMMUNICATION COMMANDS MATCH ACCESS Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength READ STRAIGHT Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength 0x40 COMM_CMD byte 2 byte byte byte 2 byte 2 ...
Page 44
COMMUNICATION COMMANDS DO & RELEASE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength SET PATH Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength WRITE SRAM PAGE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength 0x40 COMM_CMD byte 2 byte 2: ...
Page 45
COMMUNICATION COMMANDS READ CRC PROT PAGE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength READ REDIRECT PAGE W/CRC Setup Packet Encoding: bmRequestType bRequest wValue wIndex wlength selects the CRC16 generator, otherwise an 8-bit CRC is assumed. This ...
Page 46
COMMUNICATION COMMANDS SEARCH ACCESS Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength APPENDIX 3: DS2490 MODE COMMANDS, SETUP PACKET ENCODING MODE COMMANDS ENABLE PULSE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength ENABLE SPEED CHANGE Setup Packet Encoding: bmRequestType bRequest ...
Page 47
MODE COMMANDS 1-WIRE SPEED Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength STRONG PULLUP DURATION Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength PULLDOWN SLEW RATE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength 0x40 MODE_CMD MOD_1WIRE_SPEED byte 2 byte ...
Page 48
MODE COMMANDS WRITE-1 LOW TIME Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength DSOW0 RECOVERY TIME Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength APPENDIX 4: COMMAND, COMMAND TYPE CONSTANT CODES COMMAND TYPE CODES Name CONTROL_CMD COMM_CMD MODE_CMD CONTROL COMMAND ...
Page 49
MODE COMMAND CODES Name MOD_ PULSE_EN MOD_SPEED_CHANGE_EN MOD_1WIRE_SPEED MOD_STRONG_PU_DURATION MOD_PULLDOWN_SLEWRATE (Reserved) MOD_WRITE1_LOWTIME MOD_DSOW0_TREC wValue 0x0000 0x0001 0x0002 0x0003 0x0004 0x0005 0x0006 0x0007 ...
Page 50
REVISION HISTORY REVISION DATE Removed 12V V Updated ordering info to show lead-free parts only. Removed note to contact the factory for flip chip. Deleted previous Figure 9 and Table 8. Deleted DC EC Table Notes 1 and 3 and ...