System Workbench for STM32

Hello everyone,
I am just new to stm32 microcontroller. I am starting my first project of stm32 using "STM32F030C6T6" MCU. My project is to drive a "high speed solenoid valve driver".
In which I have to drive a mosfet with PWM of duty cycle 15%@40Khz. Till this point it is not a problem. but there is a twist that first pulse of PWM output must be of 500ms period i.e. 2Hz with approx. 80% duty cycle means 80%@2Hz. From 2nd pulse it should be then 15%@40Khz
Just Summarizing here:

__1st pulse : Freq. 2Hz, Period 500ms, duty cycle appr. 99%
2nd pulse: Freq. 40Hz, Period .025ms, duty cycle appr. 15%
3rd pulse: Freq. 40Hz, Period .025ms, duty cycle appr. 15%
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last pulse: Freq. 40Hz, Period .025ms, duty cycle appr. 15%

Note: Toff of all pulse from first to last should be same.__

Can any one help me how it can be done with timer or how to configure timer for it.
You feedback and suggestions will be highly appreciated.
Thanks in advance.