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the reports supported by the CP2112 and describes the configurable parameters. implement their own interface.  Users who want to integrate the device interface into their application. Figure 1. System Architecture Diagram

Table 1 lists the default values for the one-time confi gurable parameters stored in the PROM of the CP2112. should be reconfigured each time the device is reset. The suspend and SMBus pins are non-configurable. Table 1. Default PROM Values *Note: The lock bytes indicate which parameters have already been programmed. See "7.1. Get/Set Lock Byte" on page 17 for more details.

Table 2. Default Pin Settings

Table 3 lists the default settings for the SMBus. These settings are used at device power-up or reset. Table 3. SMBus Settings

Rev. 0.2 5 2. Report Overview Communication with the CP2112 is performed using HID Re ports as defined in the HI D Device Class Definition. The class definition is available for download from http://www.usb.org/developers/hidpage/. 2.1. Reports Response The CP2112 responds to reports in different ways, depending on whether the report configures a parameter on the device using a Set Report or requests data from the dev ice using a Get Report. A list of all supported reports is available in "3. Report ID List" on page 6. 2.1.1. Set Reports In response to a Set Report, the CP2112 will not return any report or acknowledgement of a report. To verify that a report has completed successfully, use the corresponding Get Report to obtain the data. The delay imposed by the HID protocol between r eports guarantees that there will be no race condition between the execution of a Set Report and Get Report verification. A Set Report will always complete before the device receives the Get Report. 2.1.2. Get Reports If a report requests data from the device and th e report is valid, the device will re turn a report with the requested data. If the report is invalid, the device will stall. 2.2. Data Format In all of the reports, the first byte of the data portion of the payload is the Repo rt ID. In the report definitions in this document, the Report ID is stored in in dex 0 of the payload and is not explicitly listed in the table. All data content in the report starts at index 1. The reports have a maximum length of 64 bytes, indexed from 0 to 63. For any multi- byte values sent in the reports, the values are sent most-significant byte first.

Table 4. Report IDs

Rev. 0.2 7 4. Device Configuration Reports 4.1. Reset Device Report ID: 0x01 Direction: Feature Request Out Reset Device is used to restart the device from the USB host. The device re-enumerates on the USB bus, and all SMBus configuration settings are reset to their default values. If any value other than 0x01 is sent with the Reset Type field of the command, the command will be ignored. For certain operating system s, such as Windows, initiating a device reset and re-enume rating will make the device's handle stale. The user application is responsible for handling this “surprise disconnect” event. See “AN496: CP2112 HID USB-to-SMBus API Specification” for more information regarding surprise disconnects. Name Offset Size Value Description Reset Type 1 1 0x01 Reset with re-enumeration

Special 3 1 0x00 Enables special functions of GPIO pins. determined by Equation 1 below. Table 5. Special Function Summary

Rev. 0.2 9 4.3. Get GPIO Values Report ID: 0x03 Direction: Feature Request In If a pin is configured as a GPIO input pin, the corresponding Latch Value bit represents the input value. If a pin is configured as a GPIO output pin, the corresponding Latch Value bit represents the logic level driven on the pin. GPIO0_TXT corresponds to bit zero (the least significant bit), and GPIO7_CLK corresponds to bit seven (the most significant bit). 4.4. Set GPIO Values Report ID: 0x04 Direction: Feature Request Out Set GPIO Values sets the values for GPIO pins. The desired value for the pin is configured in Latch Value. To drive a “1” on an output pin, the corresponding bit should be set to “1”. To drive a “0” on an output pin, the corresponding bit should be set to “0”. The Report sets new values only for output pins th at have a “1” in the corresponding bit position in Latch Mask. If the corresponding bit in Latch Mask is set to “0”, a new pin value will not be set, even if the pin is configured as an output pin. The Report does not affect any pins that are not configured as outputs. 4.5. Get Version Information Report ID: 0x05 Direction: Feature Request In Part Number indicates the device part number. The CP2112 returns 0x0C. Device Version is the version of the device. This value is not programmable over the HID interface. Name Offset Size Value Description Latch Value 1 2 * Current latch values Name Offset Size Value Description Latch Value 1 1 * Latch value Latch Mask 2 1 * Pin to se t to new latch value Name Offset Size Value Description Part Number 1 1 0x0C Device part number Device Version 2 1 Varies

10 Rev. 0.2 4.6. Get/Set SMBus Configuration Report ID: 0x06 Direction: Feature Request In/Out The values in bold are the default values. Values from the Set Report are not stored in PROM. These parameters must be initialized after every power-on or device reset. Clock Speed is the frequency of the SMBus clock in hertz (H z). It is stored as a big-endian 4-byte unsigned number. For example, to run the SMBus at 400 kHz, the value, 0x61A80, would need to be written to four clock speed bytes in this report. If a value of zero is written, this parameter is ignored. Device Address is the 7-bit slave address of the CP2112. The CP2112 will ACK this address, but the CP2112 will not respond to any read or write requests. If the least significant bit is set in this byte (read/write bit), this parameter is ignored. Write Timeout and Read Timeout are the time limits in milliseconds befo re the CP2112 automatically cancels a transfer that has been initiated. If a transfer is canceled by a write or read timeou t, the status byte of the Transfer Status Response command is set appropriately. If this value is set to 0x0000, the device continues to attempt the transfer until the transfer completes or until the Cancel Transfer command is sent. Any value greater than 1000 is ignored. SCL Low Timeout is a timeout that resets the SMBus if the SCL line is held low for more than 25 ms. If enabled and an SCL Low Timeout occurs, the status byte of the Transfer Status Response command will be set appropriately. Any value other than 0x00 and 0x01 is ignored. Retry Time is the number of attempts that the CP2112 attemp ts to complete a transfer before terminating the transfer. Any value greater than 1000 is ignored. Name Offset Size Value Description Clock Speed 1 4 0x186A0

100 KHz

SMBus Clock Speed in Hertz Device Address 5 1 0x02 Bits 7–1 make up device address (least significant bit is masked) Auto Send Read 6 1 0x00 0x01 Disabled Enabled Write Timeout 7 2 0x0000 No Timeout 0–1000 ms timeout value Read Timeout 9 2 0x0000 No Timeout 0–1000 ms timeout value SCL Low Timeout 11 1 0x00 0x01 Disabled Enabled Retry Time 12 2 0x0000 No Limit 0–1000 retries

Rev. 0.2 11 5. Data Transfer Reports 5.1. Data Read Request Report ID: 0x10 Direction: Interrupt Out Slave Address is the 7-bit address of the slave device from which data is being read. The address must be between 0xF7 and 0x02 (the least significant bit is the read/write bit and must be zero). All other values are ignored. Length is the number of bytes being requested from the slave device. The CP2112 can request between 1 and 512 bytes from a slave device. Any value outside that range is ignored. 5.2. Data Write Read Request Report ID: 0x11 Direction: Interrupt Out Slave Address is the 7-bit address of the slave device from which data is being read. The address must be between 0xF7 and 0x02 (the least significant bit is the read/write bit and must be zero). All other values are ignored. Length is the number of bytes that are being requested from the slave device. The CP2112 can request between 1 and 512 bytes from a slave device. Any value outside that range is ignored. Target Address Length is the number of bytes in the target address of the slave device from which data is being read. The target address length must be between 1 and 16. Any value outside that range is ignored. Target Address is the address of the memory location being read on the slave device. The number of bytes in the target address must match the number of bytes in targ et address length. Target Address Length specifies the number of valid address bytes in Target Address starting with the byte at Offset position 5. This type of report is used when a repeated start condition is used, which is common when accessing an EEPROM or something similar. Name Offset Size Value Description Slave Address 1 1 * Must be between 0x F7 - 0x02. Least significant bit is read/write bit and must be zero. Length 2 2 * Number of bytes (1-512 bytes) to read back Name Offset Size Value Description Slave Address 1 1 * Must be between 0xF7 and 0x02. Least significant bit is the read/write bit and must be zero. Length 2 2 * Number of bytes (1–512 bytes) to read back Target Address Length 4 1 * Number of bytes in target address (from 0x01 to 0x10) Target Address 5 16 * Address of device to be read. The number of bytes in this field must match the number of bytes speci- fied in the target length address above.

12 Rev. 0.2 5.3. Data Read Force Send Report ID: 0x12 Direction: Interrupt Out This forces the device to send a Data Read Response report when the next Interrupt IN token arrives. This is essentially polled mode reading. The PC should poll using Transfer Status Request first to determine whether data is ready. The number of bytes requested can be 1 to 512. If the number of bytes requested is greater than the number of valid bytes in the CP2112’s received bytes buffer, only the valid bytes will be returned. This command should only be used when Auto Send Read is set to 0x00. This command is ignored when Auto Send Read is set to 0x01. If a transfer is not in progress or if no data is in the buffer, this command performs no action. This command can be used while a read is in progress to retrieve the data received so far. 5.4. Data Read Response Report ID: 0x13 Direction: Interrupt In Data for Data Read Request, Data Write Request, and Data Read Force Send will be returned to the host with this report ID. Status shows the current status of the SMBus transmission. Length is the number of valid data bytes being returned to the host. Data is the actual data being returned to the host. Only the number of bytes specified in the Length field will be valid. Name Offset Size Value Description Length 1 2 * Number of valid data bytes Name Offset Size Value Description Status 1 1 0x00 0x01 0x02 0x03 Idle Busy Complete (once read, reverts to 0x00) Complete with error (once read, reverts to 0x00) Length 2 1 * Number of valid data bytes Data 3 61 * Data being returned from the SMBus slave device

Rev. 0.2 13 5.5. Data Write Report ID: 0x14 Direction: Interrupt Out Slave Address is the 7-bit address of the slave device to whic h data is being sent. The address must be between 0xF7 and 0x02 (the least significant bit is the read/write bit and must be 0). All other values are ignored. Length is the number of bytes that are being sent to the slave device. The host can transmit 1 to 61 bytes to the CP2112. Any value outside that range is ignored. Data is the actual data being sent over the SMBus to the slave device. The number of data bytes being sent in this field should match the number of bytes specified in the Length field. 5.6. Transfer Status Request Report ID: 0x15 Direction: Interrupt Out Request is used to request the current SMBus transfer status. If any value other than 0x01 is sent with the transfer status request, the command will be ignored. Name Offset Size Value Description Slave Address 1 1 * Must be between 0xF7 - 0x02. Least significant bit is read/write bit and must be zero. Length 2 1 * Number of valid data bytes Data 3 61 * Data being returned from the SMBus slave device Name Offset Size Value Description Request 1 1 0x01 Request SMBus transfer status

14 Rev. 0.2 5.7. Transfer Status Response Report ID: 0x16 Direction: Interrupt In Transfer Status Response returns information on the SMBus interface. Status 0 returns the general status of the CP2112 SMBus interface. If Status 0 is 0x00, the rest of the status bytes are not valid. Status 1 returns specific information based off of Status 0 and is dependent on the value of Status 0. Status 2 returns the number of retries before completing, being cancelled, or timing out. Status 3 returns the bytes successfully read. For example, if this report returned the following data (in hexadecimal): 16 02 05 00 05 This corresponds to: 16: Report ID (Transfer Status Response) 02: Transmission complete without errors 05: Succeeded after the following bytes retry 00: Indicates zero retries 05: Five bytes were received Name Offset Size Value Description Status 0 1 1 0x00 0x01 0x02 0x03 Idle Busy Complete (once read, reverts to 0x00) Complete with error (once read, reverts to 0x00) Status 1 2 1 * Specific conditions based on Status 0 (see below) Status 2 3 2 * Number of retries before completing, being canceled, or timing out Status 3 5 2 * Number of received bytes Status 0 Status 1 Description 0x01 0x00 0x01 0x02 0x03 Address ACKed Address NACKed Data read in progress Data write in progress 0x02 and 0x03 0x00 0x01 0x02 0x03 0x04 0x05 Timeout address NACKed Timeout bus not free (SCL Low Timeout) Arbitration lost Read incomplete Write incomplete Succeeded after Status 2 retries

Rev. 0.2 15 5.8. Cancel Transfer Report ID: 0x17 Direction: Interrupt Out Cancel is used to cancel the current SMBus transfer. If any value other than 0x01 is sent with the reset command, the command is ignored. Name Offset Size Value Description Cancel 1 1 0x01 Will cancel the current transfer. All other values are ignored

16 Rev. 0.2 6. Programmable USB Parameters The following parameters are programmable on the device. Five different reports are provided to program these parameters. Each parameter modified with these five reports can only be modified once. VID is the USB Vendor ID. PID is the USB Product ID. Power is the current requested by the device from the USB host in bus-powered mode. The units for this value are milliamps / 2. For example, if the device is configured to request 200 mA, the value for Power is 100. The maximum setting for Power is 500 mA, or a value of 250. Unpowered USB hubs are limited to providing 100 mA per port. Power Mode indicates whether the device is operating in Bus-powered (0x00), Self-powered (0x01, voltage regulator disabled) or Self-powered (0x02, voltage regulato r enabled) mode. If the device is configured for Self- powered mode, the value programmed for Power is not used during USB enumeration. Release Version is a user-programmable value. The most signific ant byte is the Major revision number. The least significant byte in the report is the Minor revision number. Both bytes can be programmed to any value from 0 to 255. Manufacturing String is a 62-byte string in which the first two byte s must be set according to the USB specification (length, 0x03). Product String is a 62-byte string in which t he first two bytes must be set according to the USB specification (length, 0x03). Serial String is a 62-byte character array used to provide a unique serial number/string for the device. The first two characters must be set according to the USB specification (length, 0x03). Name Description VID USB Vendor ID PID USB Product ID Power Power request in mA/2 Power Mode Bus Powered (0x00) Self Powered - Regulator Off (0x01) Self Powered - Regulator On (0x02) Release Version Major and Minor release version Manufacturer String Product Manufacturer Product String Product Description Serial String Serialization String Lock Byte Indicates programmed values

Rev. 0.2 17 7. PROM Programming Reports 7.1. Get/Set Lock Byte Report ID: 0x20 Direction: Feature Request In/Out The device has a 1-byte field that indicates which of the customizable fields have been programmed. The following table shows the values of the bits: If the bit value is set to 1, the corresponding field has not been customized. If the bit value is set to 0, the field has been customized or locked and can no longer be changed for this device. Using the Set Lock Byte Report, any bit value set to 0 will lock the corresponding fi eld. Send 0x00 to lock all parameters and prevent future customization. Name Offset Size Value Description Lock Status 1 1 See Below Shows which fields have already been pro- grammed. Bit Position Customizable Field Bit 0 VID Bit 1 PID Bit 2 Max Power Bit 3 Power Mode Bit 4 Release Version Bit 5 Manufacturer String Bit 6 Product String Bit 7 Serial String

18 Rev. 0.2 7.2. Get/Set USB Configuration Report ID: 0x21 Direction: Feature Request In/Out Get USB Configuration returns the values for the various fields and also the Mask value. The Mask value is equal to the most significant byte value returned in Report Get Lock Byte. If the corresponding Mask bit is set to “0”, the corresponding field has been programmed, and any Set USB Configuration function operating on that field is ignored. Set USB Configuration is used to customize thes e fields. The corresponding Mask bit should be set to “1” to program the field. If the field has already been programmed once, an attempt to reprogram it is ignored. If a field is being programmed with the current value, the programmed bit will still be set. See "7.1. Get/Set Lock Byte" on page 17 for the definition of Mask. If a parameter is being modified using this report, the corresponding bit in Mask must be set to a 1. For example, if the VID needed to be programmed, bit 0 of Mask would need to be set to a 1, and the values in VID Low Byte and VID High Byte would be written to the CP2112. 7.3. Get/Set Manufacturing String Report ID: 0x22 Direction: Feature Request In/Out The Set Manufacturing String Report can only be used once to set the Manufacturing String. Any subsequent calls to Set Manufacturing String are ignored. The maximum value for String Length is 60. The first two bytes are allocated for String Length and the value 0x03, meaning the actual length of the pstring is 62 bytes. The device will ignore the report if String Length is too long. Name Offset Size Value Description VID Low Byte 1 1 * VID Low Byte VID High Byte 2 1 * VID High Byte PID Low Byte 3 1 * PID Low Byte PID High Byte 4 1 * PID High Byte Power 5 1 * Power requested in mA/2 Power Mode 6 1 0x00 0x01 0x02 Bus Powered Self Powered - Regulator Off Self Powered - Regulator On Release Major 7 1 * Release Version Major Value Release Minor 8 1 * Release Version Minor Value Mask 9 1 * Mask for what fields to program Name Offset Size Value Description String Length 1 1 * Length of manufacturer string + 2 USB Required 2 1 0x03 Required Value Manufacturing String 3 60 * First 60 bytes of string

Rev. 0.2 19 7.4. Get/Set Product String Report ID: 0x23 Direction: Feature Request In/Out The Set Product String Report can only be used once to set the Product String. Any subsequent calls to Set Product String are ignored. The maximum value for String Length is 60. The first two bytes are allocated for String Length and the value 0x03, meaning the actual length of the payl oad part of the string is 62 byte s. The device will igno re the Report if String Length is too long. 7.5. Get/Set Serial String Report ID: 0x24 Direction: Feature Request In/Out The Set Serial String Report can only be used once to set the Product String. Any subsequent calls to Set Serial String are ignored. The maximum value for String Length is 60. The first two bytes are allocated for String Length and the value 0x03, meaning the actual leng th of the payload part of the string is 62 bytes. The device will reject the Report if String Length is too long. Name Offset Size Value Description String Length 1 1 * Length of product string + 2 USB Required 2 1 0x03 Required Value Product String 3 60 * First 60 bytes of string Name Offset Size Value Description String Length 1 1 * Length of serial string + 2 USB Required 2 1 0x03 Ser String 3 60 * 60 bytes of string

20 Rev. 0.2 APPENDIX —P IN C ONFIGURATION O PTIONS Some of the pins of the CP2112 are configurable as inputs, open-drain outputs, or push-pull outputs. These options are configured when the device has enumerated and is op erating in a normal mode. When the CP2112 is in USB suspend, all of the configurable pins are limited to be open-drain or push-pull outputs. The following describes the differences between open-drain and push-pull, and the difference in behavior in Suspend mode. See the CP2112 data sheet for the electrical specifications of the GPIO pins.  GPIO Input When a pin is configured as a GPIO input, the pin can read a logic high or logic low value. Internally, the GPIO pin is connected to the VIO pin through a resistor. If the pin is not connected externally, it will return a logic high or 1. Any voltages connected to the pin should conform to data sheet specifications.  Open-Drain Output When a pin is configured as a GPIO open-drain output, the pin can output a logic high or logic low value. The default value is logic high, and a logic high value is created by internally connecting the GPIO pin to the VIO pin through a resistor. In this mode, the pin is unable to source any current when driving a logic high. If the Set GPIO Values Report is used to change the output to a logic low, the pin is internally connected to GND.  Push-Pull Output When a pin is configured as a GPIO push-pull output, the pin can output a logic high or logic low value. When driving a logic high value, the pin is directly connected to the VIO pin internally and can source current for devices, such as LEDs. When driving a logic low value, the pin is internally connected to GND.  Suspend Mode When the device is in Suspend mode, all of the GPIO pins are forced to be open-drain or push-pull outputs. The GPIO pins retain their state during suspend mode.

Rev. 0.2 21 DOCUMENT CHANGE LIST Revision 0.1 to Revision 0.2  Updated "4.2. Get/Set GPIO Configuration" on page 8 with Special Functions.  Changed names of GPIO0 to GPIO0_TXT, GPIO1 to GPIO1_RXT, and GPIO7 to GPIO7_CLK.

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