zephyr/arch/arm/soc/atmel_sam3/Kconfig

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# Kconfig - Atmel SAM3 family processor configuration options
#
# Copyright (c) 2016 Intel Corporation.
# Copyright (c) 2014-2015 Wind River Systems, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
config SOC_ATMEL_SAM3
bool
depends on ARM
default n
if ARM && SOC_ATMEL_SAM3
config SOC_ATMEL_SAM3_EXT_SLCK
bool "Atmel SAM3 to use external crystal oscillator for slow clock"
default n
help
Says y if you want to use external 32 kHz crystal
oscillator to drive the slow clock. Note that this
adds a few seconds to boot time, as the crystal
needs to stabilize after power-up.
Says n if you do not need accraute and precise timers.
The slow clock will be driven by the internal fast
RC oscillator running at 32 kHz.
config SOC_ATMEL_SAM3_EXT_MAINCK
bool "Atmel SAM3 to use external crystal oscillator for main clock"
default n
help
The main clock is being used to drive the PLL, and
thus driving the processor clock.
Says y if you want to use external crystal oscillator
to drive the main clock. Note that this adds about
a second to boot time, as the crystal needs to
stabilize after power-up.
The crystal used here can be from 3 to 20 MHz.
Says n here will use the internal fast RC oscillator
running at 12 MHz.
config SOC_ATMEL_SAM3_PLLA_MULA
hex
default 0x06
help
This is the multiplier (MULA) used by the PLL.
The processor clock is (MAINCK * (MULA + 1) / DIVA).
Board config file can override this settings
for a particular board.
With default of MULA == 6, and DIVA == 1,
PLL is running at 7 times of main clock.
config SOC_ATMEL_SAM3_PLLA_DIVA
hex
default 0x01
help
This is the divider (DIVA) used by the PLL.
The processor clock is (MAINCK * (MULA + 1) / DIVA).
Board config file can override this settings
for a particular board.
With default of MULA == 6, and DIVA == 1,
PLL is running at 7 times of main clock.
config SOC_ATMEL_SAM3_WAIT_MODE
bool "Atmel SAM3 goes to Wait mode instead of Sleep mode"
depends on SOC_ATMEL_SAM3_EXT_MAINCK
default y if DEBUG
help
For JTAG debugging CPU clock (HCLK) should not stop. In order
to achieve this, make CPU go to Wait mode instead of Sleep
mode while using external crystal oscillator for main clock.
endif # SOC_ATMEL_SAM3