Target Practice
The bull’s eye is in the form of an STM32F030R8T6,
which is mounted on the STM32F0308-DISCO (DISCO for
DISCOVERY) evaluation board you see under the lights in
Photo 1. The evaluation board is modest in terms of
onboard goodies. However, every STM32F030R8T6 I/O
pin is pulled out to a male header post. So, you can
exercise the STM32F030R8T6 I/O subsystem to your
heart’s content.
The intent of the STM32F0308-DISCO evaluation
board is to allow low cost ARM development using an
entry-level Cortex M0 device. To that end, an onboard ST-
LINK/V2 programmer/debugger is incorporated into the
evaluation board’s design. Power is derived from the
STM32F0308-DISCO’s integral USB portal. The
STM32F0308-DISCO can also be powered externally with
+ 5 or + 3. 3 VDC.
The STM32F030R8T6
The STM32F030R8T6 is the Number 2 device in its
family when measured by its internal resources. If you are
new to ARM, there is no reason to fear this “new-to-you”
technology. ARM devices are made up of Flash, SRAM,
UARTs, SPI portals, I2C subsystems, clocks, timers, and I/O
pins. You can say the same for any other general-purpose
microcontroller. In addition, most ARM microcontrollers
are dirt cheap and deliver a mighty punch for the penny.
The STM32F030R8T6 comes standard with 64K of
Flash and 8K of SRAM. There are seven 16-bit timers, two
SPI portals, two I2C portals, two USARTs, and 18 channels
of ADC (analog-to-digital converters). Depending on how
you use its resources, the STM32F030R8T6 can man up to
55 GPIO pins. The maximum operating speed is 48 MHz
with a GPIO toggle rate of 12 MHz. If you need a
watchdog timer, the STM32F030R8T6 has one of those
pinned up too. If you count them all up, there are 11
timers available.
Operational power supply voltages for the
STM32F030R8T6 range from 2. 4 VDC to 3. 6
VDC. The STM32F030R8T6 also includes a
real time clock that can be backed by an
external battery. A useful feature of the
STM32F030R8T6 that is not found on the run-of-the-mill microcontrollers is its Sys Tick timer.
The Sys Tick timer is a free running 24-bit
countdown timer that can be used in various
ways. The ability to assign the 55 GPIO pins to
external interrupt duty is also a useful
STM32F030R8T6 quality. Interrupt handling is
supported by the STM32F030R8T6’s NVIC
(Nested Vectored Interrupt Controller).
The STM32F030R8T6 is fully supported by
datasheet documentation, reference manuals,
code libraries, and sample code. All of the
aforementioned information can be had for a
free download.
If you’re an old hat at microcontroller
design and programming but have no ARM
THE DESIGN CYCLE
ARMed and Dangerous
■ BY FRED EADY
46 February 2016
I’ve decided to ARM myself. No, I didn’t go
out and buy a fully automatic black market
M4A1, and no, I didn’t plop down big bucks
for a brand new chrome-plated Colt . 45 semiautomatic pistol. I am ARMed with a Segger
J-Link PRO that is fully supported by the
Segger Embedded Studio. By the time you
finish reading this month’s offering, you will
also be ARMed and dangerous.
■ Photo 1. There are only a couple of user LEDs and user pushbuttons
on this little evaluation board. If you want to light up the world or drive
some external relays, the STM32F0308-DISCO comes with an extra
blank printed circuit board that can be fitted to the evaluation board’s
pair of headers.
