ELCOM Euro-50, Руководство по обслуживанию

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Euro-50 Service manual
43
Elcom s. r. o.
5.5. External memory subsystem
5.5.1. RAM memory
The hardware supports SRAM 128KB. Access to the memory is non-multiplex. The width of the data bus is 8 bits. The
RAM memory is backed up by the voltage VRAM. Switching between the backup voltage VRAM and the working
VDDQ is secured by the NL3 circuit (STM795). This circuit similarly secures the external reset of the microcontroller
(after switching on the system, in the case of the loss of the voltage VDDQ), disconnecting the signal CS0n from RAM
and securing the necessary logic level of the signal CS0n during backup - minimal current consumption of RAM.
5.5.2. DataFlash memory
DS2 - DataFlash AT45DB081D-SU (8 Mbit) is used as the memory for data. DataFlash is connected to port SSP1. When
the conditions are not fulfilled for the activities of the DataFlash (switching on the system, a decline in supply volta-
ge...) the DataFlash is lead into the reset state by the signal RESETOUTn from the microcontroller.
5.5.3. SD card
The hardware allows connection of SD cards supporting SPI communication. The SD card is connected to port SSP1.
The SD card is activated by the signal SDCSn = L.
5.6. Supply 1.8V - supply voltage for the microcontroller core
A linear voltage regulator TPS76318 (NL1) is used. The input voltage of the regulator is 3.3V (VDDQ); output is 1.8V
(VDD).
5.7. Interface for connecting power supply boards
Power supply boards are connected to the motherboard via a 15-pin cable (XC5) and a 9-pin cable (XC4).
Table 5.14. Signals of interfaces for connecting power supply boards - XC4
XC5 Signal Description
1 ACCUTEMP Thermal sensor for the accumulator
2 VBAT Accupack voltage
3 VBAT Accupack voltage
4 COVER-1 Detection of accumulator cover
5 GND Relative potential
6 VDDQ 3,3V
7 VDDQ 3,3V
8 GND Relative potential
9 GND Relative potential
Table 5.15. Signals of interfaces for connecting power supply boards - XC5
XC5 Signal Description
1 VBUS Voltage from USB host
2 USBDP-1 Data driver
3 USBDN-1 Data driver
4 GND Relative potential
5 SDCLK/FCLK-2 Timeclock signal for SD card
6 SDI/FDI-2 DATA IN signal for SD card
7 GND Relative potential
8 SDDO/FDO-2 DATA OUT signal for SD card