Preliminary
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to pin, DAC or OPAMP, whereas the output can be pin, OPAMP or ADC. The current is programmable
and the OPAMP has various internal configurations such as unity gain, programmable gain using internal
resistors etc.
2.1.28 Low Energy Sensor Interface (LESENSE)
The Low Energy Sensor Interface (LESENSETM), is a highly configurable sensor interface with support
for up to 16 individually configurable sensors. By controlling the analog comparators and DAC, LESENSE
is capable of supporting a wide range of sensors and measurement schemes, and can for instance mea-
sure LC sensors, resistive sensors and capacitive sensors. LESENSE also includes a programmable
FSM which enables simple processing of measurement results without CPU intervention. LESENSE is
available in energy mode EM2, in addition to EM0 and EM1, making it ideal for sensor monitoring in
applications with a strict energy budget.
2.1.29 Backup Power Domain
The backup power domain is a separate power domain containing a Backup Real Time Counter, BURTC,
and a set of retention registers, available in all energy modes. This power domain can be configured to
automatically change power source to a backup battery when the main power drains out. The backup
power domain enables the EFM32GG990 to keep track of time and retain data, even if the main power
source should drain out.
2.1.30 Advanced Encryption Standard Accelerator (AES)
The AES accelerator performs AES encryption and decryption with 128-bit or 256-bit keys. Encrypting or
decrypting one 128-bit data block takes 52 HFCORECLK cycles with 128-bit keys and 75 HFCORECLK
cycles with 256-bit keys. The AES module is an AHB slave which enables efficient access to the data
and key registers. All write accesses to the AES module must be 32-bit operations, i.e. 8- or 16-bit
operations are not supported.
2.1.31 General Purpose Input/Output (GPIO)
In the EFM32GG990, there are 86 General Purpose Input/Output (GPIO) pins, which are divided into
ports with up to 16 pins each. These pins can individually be configured as either an output or input. More
advances configurations like open-drain, filtering and drive strength can also be configured individually
for the pins. The GPIO pins can also be overridden by peripheral pin connections, like Timer PWM
outputs or USART communication, which can be routed to several locations on the device. The GPIO
supports up to 16 asynchronous external pin interrupts, which enables interrupts from any pin on the
device. Also, the input value of a pin can be routed through the Peripheral Reflex System to other
peripherals.
2.1.32 Liquid Crystal Display Driver (LCD)
The LCD driver is capable of driving a segmented LCD display with up to segments. A voltage boost
function enables it to provide the LCD display with higher voltage than the supply voltage for the device.
In addition, an animation feature can run custom animations on the LCD display without any CPU inter-
vention. The LCD driver can also remain active even in Energy Mode 2 and provides a Frame Counter
interrupt that can wake-up the device on a regular basis for updating data.
2.2 Configuration Summary
The features of the EFM32GG990 is a subset of the feature set described in the EFM32GG Reference
Manual. Table 2.1 (p. 7) describes device specific implementation of the features.
Table 2.1. Configuration Summary
Module
Configuration
Pin Connections
Cortex-M3
Full configuration
NA
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2012-09-11 - EFM32GG990FXX - d0046_Rev1.00
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