Leading-edge architecture with

Cortex-M3 core

■

Harvard architecture

■

1.25 DMIPS/MHz and 0.19 mW/MHz

■

Thumb-2 instruction set brings 32-bit performance

with 16-bit code density

■

Single cycle multiply and hardware division

■

Embedded, fast interrupt controller is now inside the

core allowing:

■

Excellent real-time behaviour

■

Low latency down to six CPU cycles inter-interrupt

■

Six CPU cycles wake-up time from low-power mode

■

Up to 35% faster and up to 45% less code than

ARM7TDMI®

STM32 key benefits

Outstanding power efficiency

High performance does not mean high power

consumption. We have taken special care to address

three main energy requirements driven by the market:

■

High dynamic power efficiency in running mode

■

Extremely low power when the application is

in standby

■

Low-voltage capability for direct battery operation

In run mode, executing from Flash at full 72 MHz CPU

speed, the STM32 has a current consumption as low

as 27 mA.

Stop

Standby

RTC on

Standby

RTC off

RTC V

bat

V

dd: 3.3 V

µA typical

@ 25 °C

14 µA

3.4 µA

2 µA

1.4 µA

STM32F10x: Low power

In standby mode, current consumption is as low as

2 µA typical, with reset circuitry active. Finally, its 2.0 V

to 3.6 V power supply enables its use for battery

operated applications.

The STM32 has three different low power modes and

a versatile clocking scheme so that users can optimize

power consumption versus performance.

The STM32 also embeds a real-time clock (RTC) running

either from a 32 kHz quartz oscillator or an internal

RC. The RTC has a separate power domain, with an

embedded switchover to run either from a dedicated coin

cell battery or from the main supply. Its typical current

consumption is 1.4 µA at 3.3 V. It embeds 20 bytes for

data backup. Start-up time from low-power modes is

lower than 7 µs typical from stop mode, and 55 µs typical

from standby mode and reset.

Drysthone

rating

100

80

60

40

20

0

0

10

20

30

40

50

60

70

f

CPU (MHz)

Cortex-M3

(Thumb-2)

ARM7TDMI

(ARM)

ARM7TDMI

(Thumb)

IRQ1

ARM7

Interrupt handling

in assembler code

Cortex-M3

Interrupt handling

in HW

PUSH

POP

ISR 1

26-42

16

PUSH

POP

ISR 1

12

12

Cortex-M3 performance versus ARM7TDMI

Cortex-M3 interrupt versus ARM7TDMI

■

Low voltage 2.0 V to 3.6 V operation

■

27 mA in run mode from Flash at 72 MHz

■

Startup time from stop

< 7 µs

Startup time from standby

55 µs

■

Reset circuitry always active