Description
STM32F405xx, STM32F407xx
2.2.9
Flexible static memory controller (FSMC)
The FSMC is embedded in the STM32F405xx and STM32F407xx family. It has four Chip
Select outputs supporting the following modes: PCCard/Compact Flash, SRAM, PSRAM,
NOR Flash and NAND Flash.
Functionality overview:
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Write FIFO
Maximum FSMC_CLK frequency for synchronous accesses is 60 MHz.
LCD parallel interface
The FSMC can be configured to interface seamlessly with most graphic LCD controllers. It
supports the Intel 8080 and Motorola 6800 modes, and is flexible enough to adapt to
specific LCD interfaces. This LCD parallel interface capability makes it easy to build cost-
effective graphic applications using LCD modules with embedded controllers or high
performance solutions using external controllers with dedicated acceleration.
2.2.10
Nested vectored interrupt controller (NVIC)
The STM32F405xx and STM32F407xx embed a nested vectored interrupt controller able to
manage 16 priority levels, and handle up to 82 maskable interrupt channels plus the 16
interrupt lines of the Cortex™-M4F.
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Closely coupled NVIC gives low-latency interrupt processing
Interrupt entry vector table address passed directly to the core
Allows early processing of interrupts
Processing of late arriving, higher-priority interrupts
Support tail chaining
Processor state automatically saved
Interrupt entry restored on interrupt exit with no instruction overhead
This hardware block provides flexible interrupt management features with minimum interrupt
latency.
2.2.11
2.2.12
External interrupt/event controller (EXTI)
The external interrupt/event controller consists of 23 edge-detector lines used to generate
interrupt/event requests. Each line can be independently configured to select the trigger
event (rising edge, falling edge, both) and can be masked independently. A pending register
maintains the status of the interrupt requests. The EXTI can detect an external line with a
pulse width shorter than the Internal APB2 clock period. Up to 140 GPIOs can be connected
to the 16 external interrupt lines.
Clocks and startup
On reset the 16 MHz internal RC oscillator is selected as the default CPU clock. The
16 MHz internal RC oscillator is factory-trimmed to offer 1% accuracy over the full
temperature range. The application can then select as system clock either the RC oscillator
or an external 4-26 MHz clock source. This clock can be monitored for failure. If a failure is
detected, the system automatically switches back to the internal RC oscillator and a
software interrupt is generated (if enabled). This clock source is input to a PLL thus allowing
to increase the frequency up to 168 MHz. Similarly, full interrupt management of the PLL
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DocID022152 Rev 4
STMICROELECTRONICS [ ST ]
