Using the systick timer or the WDT as you showed is the usual ARM M0 way. But in PSoCs (or PRoCs) is a bit more: there are components. Open the Topdesign view and drag a Timer Counter PWM - component onto your schematic screen. You may add a new page beforehand to better overview what you do. This component together with a clock component can be used to generate a one minute timer quite easy. The output can be connected to an isr component to get interrupted. With the component's APIs you are able to control (start/stop/reset etc) the TCPWM.