參數(shù)資料
型號: PSD401A1-C-70U
廠商: 意法半導體
英文描述: Low Cost Field Programmable Microcontroller Peripherals
中文描述: 低成本現(xiàn)場可編程微控制器外圍設備
文件頁數(shù): 64/123頁
文件大小: 657K
代理商: PSD401A1-C-70U
PSD4XX Famly
61
9.4 Memory Block
The PSD4XX provides EPROM memory for code storage and SRAM memory for scratch
pad usage. Chip selects for the memory blocks come from the DPLD decoding logic and
are defined by the user in the PSDsoft Software. Figure 32 shows the organization of the
Memory Block.
The PSD4XX family uses Zero-power memory techniques that place memory into Standby
Mode between MCU accesses. The memory becomes active briefly after an address
transition, then delivers new data to the outputs, latches the outputs, and returns to standby.
This is done automatically and the designer has to do nothing special to benefit from this
feature. Both the EPROM and SRAM have this feature.
9.4.1 EPROM
The PSD4XX provides three EPROM densities: 256Kbit, 512Kbit, or 1Mbit. The EPROM
is divided into four 8K, 16K or 32K byte blocks. Each block has its own chip select signals
(ES0 – ES3). The EPROM can be configured as 32K x 8, 64K x 8 or 128K x 8 for
microcontrollers with an 8-bit data bus. For 16-bit data buses, the EPROM is configured as
16K x 16, 32K x 16 or 64K x 16.
9.4.2 SRAM
The SRAM has 16Kbits of memory, organized as 2K x 8 or 1K x 16. The SRAM is enabled
by chip select signal RS0 from the DPLD. The SRAM has a battery back-up (STBY) mode.
This back-up mode is invoked when the V
CC
voltage drops under the Vstdby voltage by
approximately 0.7 V. The Vstdby voltage is connected only to the SRAM and cannot be
lower than 2.7 volts.
9.4.3 Memory Select Map
The EPROM and SRAM chip select equations are defined in the ABEL file in terms of
address and other DPLD inputs. The memory space for the EPROM chip select
(ES0 – ES3) should not be larger than the EPROM block (8KB, 16KB, or 32KB) it is
selecting.
The following rules govern how the internal PSD4XX memory selects/space are defined:
J
The EPROM blocks address space cannot overlap
J
SRAM, internal I/O and Peripheral I/O space cannot overlap
J
SRAM, internal I/O and Peripheral I/O space can overlap EPROM space, with
priority given to SRAM or I/O. The portion of EPROM which is overlapped
cannot be accessed.
The Peripheral I/O space refers to memory space occupied by peripherals when Port A is
configured in the Peripheral I/O Mode.
The PSD4XX
Architecture
(cont.)
相關PDF資料
PDF描述
PSD401A1-C-90JI Low Cost Field Programmable Microcontroller Peripherals
PSD411A1-C-15J High Speed CMOS Logic Dual 2-to-4 Line Decoders/Demultiplexers 16-SOIC -55 to 125
PSD411A1-C-15L High Speed CMOS Logic Dual 2-to-4 Line Decoders/Demultiplexers 16-SOIC -55 to 125
PSD411A1-C-15U High Speed CMOS Logic Dual 2-to-4 Line Decoders/Demultiplexers 16-SOIC -55 to 125
PSD411A1-C-70J High Speed CMOS Logic Dual 2-to-4 Line Decoders/Demultiplexers 16-SOIC -55 to 125
相關代理商/技術參數(shù)
參數(shù)描述
PSD401A1-C-90JI 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low Cost Field Programmable Microcontroller Peripherals
PSD401A1C-90JI 制造商:STMicroelectronics 功能描述:Field Programmable Microcontroller Peripherals
PSD401A1-C-90UI 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low Cost Field Programmable Microcontroller Peripherals
PSD401A2 制造商:未知廠家 制造商全稱:未知廠家 功能描述:PSD4XX/ZPSD4XX FAMILY FIELD-PROGRAMMABLE MICROCONTROLLER PERIPHERALS
PSD401A2-12J 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Field-Programmable Peripheral