In this two part series guide on how to create a library for PCF8591 AD/DA (Analog to Digital/ Digital to Analog) that can be used with any microcontroller (STM32F4 in this case).
In this guide, we shall cover the following:
- Gathering the required information.
- Connection.
- STM32CubeIDE setup.
1. Gathering the Required Information:
Since this guide focuses on how to create library for the module, we shall start from the datasheet.
The datasheet can be found here or by simply googling PCF8591 datasheet.
From the datasheet:
Control byte to choose the ADC mode and enable the DAC or not.
DAC section:
From the dynamics characteristics, we can find the maximum clock frequency of 100KHz for the I2C bus as following:
The ADC reading sequence and DAC write sequence:
Since we get all the needed, we can start developing the library.
2. Connection:
Since the board used in this guide is STM32F411RE Nucleo-64.
The board features Arduino Uno pinout, D14 and D15 features I2C pins as shown below:
These pins can be found in the pinout in the user manual of STM32 Nucleo-64 boards (MB1136) as following:
- PB8(D15) is SCL which is Serial Clock.
- PB9(D14) is SDA which is Serial Data.
Hence, the connection as following:
3. STM32CubeIDE Setup:
Open STM32CubeIDE after selecting the workspace and create new project as following:
Select the MCU:
Give the project a name:
Make sure the Targeted Project Type is STM32Cube, Language is C and binary type is Executable.
After that, set PB8 and PB9 for I2C1 or I2C3, here we shall use I2C1 as following:
Also, set PA2 and PA3 for Serial2 since they are linked with VCP of onboard ST-Link.
Enable UART as following:
Next Enable I2C1 as following:
From parameter Settings of I2C1 enable the fast mode as following:
From Clock Configuration tab, set the frequency to maximum of 100MHz as following:
From Project Manager tab, select Code Generation and enable Generate peripheral initialization as pair of .c/.h files per peripheral as following:
Thats all for the configuration.
Save the project and this will generate the project.
In part 2, we start developing the library.
Happy coding 😉
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