Memories; Dma (Direct Memory Access); Lcd (Liquid Crystal Display) - STMicroelectronics STM32L151CB Manual

STM32L151xx, STM32L152xx
3.7

Memories

The STM32L15xxx devices have the following features:
●
Up to 16 Kbyte of embedded RAM accessed (read/write) at CPU clock speed with 0
wait states. With the enhanced bus matrix, operating the RAM does not lead to any
performance penalty during accesses to the system bus (AHB and APB buses).
●
The non-volatile memory is divided into three arrays:
–
–
–
The options bytes are used to write-protect the memory (with 4 KB granularity) and/or
readout-protect the whole memory with the following options:
–
–
–
The whole non-volatile memory embeds the error correction code (ECC) feature.
3.8

DMA (direct memory access)

The flexible 7-channel, general-purpose DMA is able to manage memory-to-memory,
peripheral-to-memory and memory-to-peripheral transfers. The DMA controller supports
circular buffer management, avoiding the generation of interrupts when the controller
reaches the end of the buffer.
Each channel is connected to dedicated hardware DMA requests, with software trigger
support for each channel. Configuration is done by software and transfer sizes between
source and destination are independent.
The DMA can be used with the main peripherals: SPI, I
and ADC.
3.9

LCD (liquid crystal display)

The LCD drives up to 8 common terminals and 44 segment terminals to drive up to 320
pixels.
●
Internal step-up converter to guarantee functionality and contrast control irrespective of
V
DD
the voltage to the LCD
●
Supports static, 1/2, 1/3, 1/4 and 1/8 duty
●
Supports static, 1/2, 1/3 and 1/4 bias
●
Phase inversion to reduce power consumption and EMI
●
Up to 8 pixels can be programmed to blink
●
Unneeded segments and common pins can be used as general I/O pins
●
LCD RAM can be updated at any time owing to a double-buffer
●
The LCD controller can operate in Stop mode
32, 64 or 128 Kbyte of embedded Flash program memory
4 Kbyte of data EEPROM
Options bytes
Level 0: no readout protection
Level 1: memory readout protection, the Flash memory cannot be read from or
written to if either debug features are connected or boot in RAM is selected
Level 2: chip readout protection, debug features (Cortex-M3 JTAG and serial wire)
and boot in RAM selection disabled (JTAG fuse)
. This converter can be deactivated, in which case the V
Doc ID 17659 Rev 6
Functional overview
2
C, USART, general-purpose timers
pin is used to provide
LCD
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