SW4STM32C datasheet(71/99 Pages) STMICROELECTRONICS

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Debug through hardware exploration

As a complement to software instrumentation, a user facing a non-working system may take

great advantage to monitor STM32 pin states (GPIO or clock among others) with external

tools such as oscilloscopes or logic analyzers.

This chapter presents the possibilities offered by STMicroelectronics hardware kits and

integrates a complete tutorial to setup the microcontroller clock output (MCO)

8.1

Easy pinout probing with STMicroelectronics hardware kits

All STMicroelectronics hardware kits presented in Section 2.1.1 on page 9 offers easy

pinout access thanks to their Morpho or Arduino™ connectors.

The coverage of the pinout by the connectors depends on the board itself as well as on the

MCU type. In most cases, a large number of GPIOs are covered.

In order to use this coverage at best, the user is advised to study the board schematics that

show the connections between the MCU pins and the connectors. In association with the

schematics, the board user manual presents the jumper and solder bridge configurations

that modify the routing of pins to connectors.

8.2

Microcontroller clock output (MCO)

This feature allows to output one or more internal clock to one or more pins in order to

enable measurement through an external tool, typically an oscilloscope.

It can be useful in debug context in order to check that clock settings is as per expectation

and help to investigate potential error in clock tree initialization code.

8.2.1

Configuration with STM32CubeMX

In STM32CubeMX, MCO stands for master clock output. It is enabled by ticking the Master

Clock Output option in the RCC section as shown in Figure 52.

Figure 52. MCO pin selection in STM32CubeMX

This allocates a pin labeled RCC_MCO.

SW4STM32C Datasheet(PDF) 71 Page - STMicroelectronics