...the world's most energy friendly microcontrollers
2014-07-02 - Tiny Gecko Family - d0034_Rev1.20
12
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• Continuous storage of data requiring different byte lengths
• Data access in a single core clock cycle
• Integrated power modes
• Sleep Now mode for immediate transfer to low power state
• Sleep on Exit mode for entry into low power state after the servicing of an interrupt
• Ability to extend power savings to other system components
• Optimized for low latency, nested interrupts
4.3 Functional Description
For a full functional description of the ARM Cortex-M3 (r2p1) implementation in the EFM32TG family,
the reader is referred to the EFM32 Cortex-M3 Reference Manual.
4.3.1 Interrupt Operation
Figure 4.1. Interrupt Operation
Module
Cort ex - M3 NVIC
IEN[n]
IF[n]
set
clear
IFS[n]
IFC[n]
Int errupt
condit ion
IRQ
SETENA[n]/ CLRENA[n]
Int errupt
request
SETPEND[n]/ CLRPEND[n]
set
clear
Act ive int errupt
Soft ware generat ed int errupt
The EFM32TG devices have up to 23 interrupt request lines (IRQ) which are connected to the Cortex-
M3. Each of these lines (shown in Table 4.1 (p. 12) ) are connected to one or more interrupt flags in
one or more modules. The interrupt flags are set by hardware on an interrupt condition. It is also possible
to set/clear the interrupt flags through the IFS/IFC registers. Each interrupt flag is then qualified with its
own interrupt enable bit (IEN register), before being OR'ed with the other interrupt flags to generate the
IRQ. A high IRQ line will set the corresponding pending bit (can also be set/cleared with the SETPEND/
CLRPEND bits in ISPR0/ICPR0) in the Cortex-M3 NVIC. The pending bit is then qualified with an enable
bit (set/cleared with SETENA/CLRENA bits in ISER0/ICER0) before generating an interrupt request to
the core. Figure 4.1 (p. 12) illustrates the interrupt system. For more information on how the interrupts
are handled inside the Cortex-M3, the reader is referred to the EFM32 Cortex-M3 Reference Manual.
Table 4.1. Interrupt Request Lines (IRQ)
IRQ #
Source
0
DMA
1
GPIO_EVEN
2
TIMER0
3
USART0_RX
4
USART0_TX
5
ACMP0/ACMP1
6
ADC0
7
DAC0
8
I2C0
9
GPIO_ODD
Summary of Contents for EFM32TG
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