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resources:tools-software:uc-drivers:ltc2672 [03 Feb 2023 04:46] – updated contents Jose Ramon San Buenaventura | resources:tools-software:uc-drivers:ltc2672 [06 Apr 2023 04:42] (current) – Marc Sosa | ||
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====== LTC2672 - No-OS Driver ====== | ====== LTC2672 - No-OS Driver ====== | ||
- | ===== Supported Devices | + | ==== Supported Devices ==== |
* [[adi> | * [[adi> | ||
+ | ==== Evaluation Boards ==== | ||
+ | * [[ADI> | ||
+ | \\ | ||
===== Overview ===== | ===== Overview ===== | ||
- | The LTC2672 is a family of five-channel, | + | The [[adi>LTC2672]] is a family of five-channel, |
+ | |||
+ | The channels | ||
+ | |||
+ | The [[adi>LTC2672]] includes a precision integrated 1.25 V reference (10 ppm/°C maximum), with the option to use an external reference. The serial peripheral interface (SPI)-compatible, | ||
- | === Applications === | + | ==== Applications |
- | * Tunable | + | * Tunable |
* Semiconductor optical amplifier biasing | * Semiconductor optical amplifier biasing | ||
* Resistive heaters | * Resistive heaters | ||
- | * Current mode biasing | + | * Current-mode biasing |
- | {{ : | + | {{ : |
===== ADI No-OS ===== | ===== ADI No-OS ===== | ||
- | The goal of ADI Microcontroller No-OS is to be able to provide reference projects for lower end processors, which can't run Linux, or aren't running a specific operating system, to help those customers using microcontrollers with ADI parts. ADI No-OS offers **generic drivers** which can be used as a base for any microcontroller platform and also **example projects** which are using these drivers on various microcontroller platforms. | + | The goal of ADI Microcontroller No-OS is to provide reference projects for lower end processors, which can't run Linux or aren't running a specific operating system, |
- | + | ||
- | For more information about ADI No-OS and supported microcontroller platforms see: [[: | + | |
+ | For more information about ADI No-OS and supported microcontroller platforms, visit the [[: | ||
+ | \\ | ||
+ | \\ | ||
===== LTC2672 ADI No-OS driver ===== | ===== LTC2672 ADI No-OS driver ===== | ||
- | + | ==== Driver Source Code ==== | |
- | ==== LTC2672 | + | |
The source code for LTC2672 driver can be found here: | The source code for LTC2672 driver can be found here: | ||
- | <WRAP round download | + | <WRAP round center |
* {{https:// | * {{https:// | ||
* {{https:// | * {{https:// | ||
</ | </ | ||
- | The driver also uses the ADI util library, so make sure you also add the necessary files in your project. The source code for the util library can be found here: | + | This driver also uses the ADI utility |
- | <WRAP round download | + | <WRAP round center |
* {{https:// | * {{https:// | ||
* {{https:// | * {{https:// | ||
</ | </ | ||
- | In order to be able to use this driver | + | To use the LTC2672 No-OS Driver, |
- | If the SPI communication is chosen, there are three functions which are called by the ADXL355 | + | If the SPI communication is chosen, there are three functions which are called by the LTC2672 |
- | * no_os_spi_init() | + | <WRAP center box 60%> |
- | * no_os_spi_write_and_read() | + | | **no_os_spi_init()** | initializes the communication peripheral. |
- | * no_os_spi_remove() | + | | **no_os_spi_write_and_read()** | writes and reads data to/from the device. |
+ | | **no_os_spi_remove()** | deinitializes the communication peripheral. | ||
+ | </ | ||
And there are two data types that have to be defined: | And there are two data types that have to be defined: | ||
- | | + | <WRAP center box 60%> |
- | * no_os_spi_init_param | + | | **no_os_spi_desc** | structure holding the SPI descriptor |
+ | | **no_os_spi_init_param** | structure holding the parameters for SPI initialization | ||
+ | </ | ||
+ | An example of a header file containing the prototypes of the functions which have to be implemented, | ||
- | An example of a header file containing the prototypes of the functions which have to be implemented, | + | <WRAP round center |
- | + | ||
- | <WRAP round download | + | |
* {{https:// | * {{https:// | ||
</ | </ | ||
- | ==== LTC2672 | + | ==== Code Documentation ==== |
- | Source code documentation for the driver is automatically generated using the Doxygen tool and it is available below: | + | Source code documentation for the driver is automatically generated using the Doxygen tool and can be accessed in these links: |
+ | <WRAP round center download 80%> | ||
* [[http:// | * [[http:// | ||
* [[http:// | * [[http:// | ||
+ | </ | ||
- | + | ==== Device Configuration ==== | |
- | ==== LTC2672 | + | |
=== Driver Initialization === | === Driver Initialization === | ||
- | In order to use the device, you will have to provide the support for the communication protocol (SPI) as mentioned above. | + | To use the device, you need to provide the support for the communication protocol (SPI) as mentioned above. |
- | The first API to be called is **ltc2672_init**. Make sure that it returns 0, indicating | + | \\ |
+ | \\ | ||
+ | The first API function | ||
+ | \\ | ||
+ | \\ | ||
=== Output Span Configuration === | === Output Span Configuration === | ||
- | Each channel' | + | |
- | + | Use either of the following functions to configure the channel output span: | |
- | The current driver and evaluation hardware only supports the default VREF and FSADJ settings of the LTC2672. For settings other than the default, appropriate scaling of the output span and desired current must be performed. For reference, refer to Table 9 of [[adi>media/ | + | <WRAP center box 80%> |
+ | | **ltc2672_set_span_channel** | allows each channel' | ||
+ | | **ltc2672_set_span_all_channels** | sets same output span across all channels | ||
+ | </ | ||
+ | <note important> | ||
=== Monitor Multiplexer Output Configuration === | === Monitor Multiplexer Output Configuration === | ||
- | The LTC2672 contains a multiplexer pin output which allows an external controller or Analog-to-Digital Converter | + | The [[ADI>LTC2672]] contains a multiplexer pin output, which allows an external controller or analog-to-digital converter |
- | + | \\ | |
- | == Current Measurement using Multiplexer | + | \\ |
- | The output current from any one channel can be measured by configuring the multiplexer | + | **Current Measurement using Multiplexer |
+ | \\ | ||
+ | The output current from any one channel can be measured by configuring the multiplexer | ||
+ | < | ||
I_OUTx = I_FS(mA) * V_MUX / V_REF | I_OUTx = I_FS(mA) * V_MUX / V_REF | ||
- | + | </ | |
- | Where V_REF is the measurement from the VREF pin (~1.25V). | + | where: |
- | I_FS(mA) is the output span setting in mA. | + | \\ |
- | + | **V_REF** is the measurement from the VREF pin (~1.25V). | |
- | + | \\ | |
- | The current isn't directly measured but instead estimated from the DAC settings of the specified channel. This means that the measurement using the above equation is only valid when the output is properly terminated (not open / dropping out) and the output span is configured to a valid value (refer to header implementation). | + | **I_FS(mA)** is the output span setting in mA. |
- | + | \\ | |
- | + | \\ | |
- | + | The current isn't directly measured, but instead estimated from the DAC settings of the specified channel. This means that the measurement using the above equation is only valid when the output is properly terminated (not open/ | |
- | == Die Temperature Measurement using Multiplexer Output | + | \\ |
- | Similar with the output current, the die temperature of the LTC2672 can also be measured through the **ltc2672_monitor_mux** function. The voltage at the multiplexer output pin varies directly with the temperature with a temperature coefficient of -3.7mV / °C. The die temperature can be estimated | + | \\ |
+ | **Die Temperature Measurement using Multiplexer Output** | ||
+ | \\ | ||
+ | Similar with the output current, the die temperature of the [[ADI>LTC2672]] can also be measured through the **ltc2672_monitor_mux** function. The voltage at the multiplexer output pin varies directly with the temperature with a temperature coefficient of -3.7 mV/°C. The die temperature can be estimated | ||
+ | < | ||
T = T0 + (V0 − V_MUX) / (3.7 mV/°C). | T = T0 + (V0 − V_MUX) / (3.7 mV/°C). | ||
- | + | </ | |
- | Where T0 = 25°C, initial temperature. | + | where: |
- | V0 = 1.4 V, initial voltage. | + | \\ |
+ | **T0 = 25°C** (initial temperature). | ||
+ | \\ | ||
+ | **V0 = 1.4 V** (initial voltage). | ||
+ | \\ | ||
For calibration or more accurate measurements, | For calibration or more accurate measurements, | ||
+ | \\ | ||
+ | \\ | ||
+ | === Output Current Configuration === | ||
+ | Once the channel output spans have been set, you may now configure the output current using the following functions: | ||
+ | |**ltc2672_set_current_channel**| allows output current to be individually set per channel | | ||
+ | | **ltc2672_set_current_all_channels** | sets similar output current across all channels (given that they have the same output span) | | ||
+ | < | ||
+ | \\ | ||
+ | **Load Termination and Combining Multiple Channels** | ||
+ | \\ | ||
+ | Each output channel of the [[ADI> | ||
- | === Output Current Configuration === | + | Once the desired channels |
- | Once the channel output spans have been set, the current | + | |
- | **Note:** When the output | + | < |
+ | === Power Down Options === | ||
+ | To save power, you may use the following functions: | ||
+ | | **ltc2672_power_down_channel** | used to power down single or multiple channels | | ||
+ | | **ltc2672_power_down_all_channels** | used to power down all channels | | ||
+ | | **ltc2672_chip_power_down** | used to power down the entire chip, shutting down all other blocks such as the internal reference | | ||
+ | \\ | ||
+ | === Output Current Toggle Configuration === | ||
+ | For instances requiring the DAC outputs to toggle between two levels, the [[adi> | ||
+ | <WRAP center box 50%> | ||
+ | | ||
+ | \\ | ||
+ | | ||
+ | </ | ||
+ | Once set up, perform the toggle by repeatedly using the **ltc2672_global_toggle** function as needed. The output levels can be verified by connecting an ammeter on the output of the desired channel and measuring the current levels during state changes. | ||
+ | \\ | ||
+ | \\ | ||
+ | === Fault Register Bits === | ||
+ | The first 8 bits of an SPI transaction response serve as fault indicators. Whenever a fault is detected, the corresponding Fault Register bit is set and is outputted on the next SPI transaction. If an SPI transaction fixes any of the existing faults, the cleared fault register bit is reflected on the next SPI transaction response. The faults that are detected include open circuit detection for any of the output channels, overtemperature detection (> 175°C) with thermal protection, and invalid SPI transaction length (valid lengths are 24, 32, and multiple of 32 bits). | ||
+ | \\ | ||
+ | \\ | ||
+ | == Configuration Command == | ||
+ | |**ltc2672_config_command** | allows disabling of any of the active fault detection mechanisms. This function can also disable the open circuit detection and thermal protection mechanism, as well as provide means to configure the external reference operation. | | ||
- | == Load Termination and Combining Multiple Channels == | + | For the valid corresponding mask or values, refer to the device data sheet. |
- | Each output channel of the LTC2672 can output a maximum of 300mA. In instances where current greater than 300mA is needed, multiple channels can be tied together | + | \\ |
+ | \\ | ||
+ | ==== Driver Initialization Example ==== | ||
- | Once the desired channels have been set to have similar output span, the target current can then be set by configuring the same channels via **ltc2672_set_current_channel**. For example, channels 0 and 1 can be combined to produce 350mA of current by configuring one channel to have 300mA output while the other at 50mA (assuming they' | + | === Example Initialization Using Maxim SDK as Platform === |
+ | < | ||
+ | int ret; | ||
- | **Note:** All Output pins must be terminated to GND. Unused pins must remain unconnected or floating for proper operation. | + | struct ltc2672_dev |
+ | |||
+ | struct max_spi_init_param spi_extra = { | ||
+ | .numSlaves = 1, | ||
+ | .polarity = SPI_SS_POL_LOW, | ||
+ | }; | ||
- | === Power Down Options | + | struct ltc2672_init_param ltc2672_init_params |
- | Single or multiple channels can be powered down by using the **ltc2672_power_down_channel** or **ltc2672_power_down_all_channels** respectively to save power. Other than the channel power down, there' | + | .spi_init.device_id |
+ | .spi_init.max_speed_hz | ||
+ | .spi_init.chip_select | ||
+ | .spi_init.mode | ||
+ | .spi_init.bit_order | ||
+ | .spi_init.platform_ops = & | ||
+ | .spi_init.extra = & | ||
+ | .active_device = LTC2672_12, | ||
+ | }; | ||
+ | ret = ltc2672_init(& | ||
+ | if (ret) | ||
+ | return ret; | ||
+ | bool toggle_flag = false; | ||
+ | float current_set = (float)3.125 / (float)1; | ||
+ | uint32_t command; | ||
- | === Output Current Toggle Configuration === | + | /* Set all channels for 6.25mA output span */ |
- | For instances that require the DAC outputs to toggle between two levels, the LTC2672 offers a toggle function which allows two current values to be stored in a channel' | + | ret = ltc2672_set_span_all_channels(ltc2672_desc, LTC2672_100VREF); |
+ | if (ret) | ||
+ | return ret; | ||
- | Once setup, perform the toggle by repeatedly using the **ltc2672_global_toggl** API as needed. The output levels can be verified by connecting an ammeter on the output | + | /* Set current |
+ | ret = ltc2672_set_current_all_channels(ltc2672_desc, | ||
+ | if (ret) | ||
+ | return ret; | ||
+ | /* Monitor the Voltage Reference Level via Multiplexer Output */ | ||
+ | ret = ltc2672_monitor_mux(ltc2672_desc, | ||
+ | if (ret) | ||
+ | return ret; | ||
+ | /* Power Down All channels and Voltage Reference */ | ||
+ | ret = ltc2672_chip_power_down(ltc2672_desc); | ||
+ | if (ret) | ||
+ | return ret; | ||
- | === Fault Register Bits === | + | /* Setup Channel 3 to toggle bet. 1.5mA and 1.9mA */ |
- | The first 8 bits of a SPI transaction response serve as fault indicators. Whenever a fault is detected, the corresponding Fault Register bit is set and is outputted on the next SPI transaction. If a SPI transaction fixes any of the existing faults, the cleared fault register bit is reflected on the next SPI transaction response. The faults that are detected include open circuit detection for any of the output channels, overtemperature detection (> 175°C) with thermal protection, and invalid SPI transaction length | + | ret = ltc2672_setup_toggle_channel(ltc2672_desc, LTC2672_DAC3, |
+ | if (ret) | ||
+ | return ret; | ||
+ | /* Enable CH3 for toggling */ | ||
+ | ret = ltc2672_enable_toggle_channel(ltc2672_desc, | ||
+ | if (ret) | ||
+ | return ret; | ||
- | == Configuration Command == | + | /* Repeated Toggle of CH3 DAC output */ |
- | Using the **ltc2672_config_command** allows disabling of any of the active fault detection mechanisms of the part. The open circuit detection and thermal protection mechanism can be disabled via this command. The external reference operation is also configurable via this command. For the valid corresponding mask or values, refer to the device data sheet. | + | for(int i = 0; i < 4; i++){ |
+ | toggle_flag ^= true; | ||
- | + | ret = ltc2672_global_toggle(ltc2672_desc, | |
- | ==== LTC2672 | + | if (ret) |
+ | return ret; | ||
+ | } | ||
+ | </ | ||
+ | \\ | ||
+ | \\ | ||
+ | ==== Driver | ||
+ | <WRAP center round tip 100%> | ||
+ | You can find application example projects for LTC2672 driver here: [[resources: | ||
+ | </ | ||