BORA SOM/BORA Hardware/General Information/Processor and memory subsystem

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Processor and memory subsystem[edit | edit source]

The heart of Bora module is composed of the following components:

  • Xilinx Zynq Z-7010 (XC7Z010) / Z-7020 (XC7Z020) SoC
  • Power supply unit
  • DDR memory banks
  • NOR and NAND flash banks
  • 3x 140 pin connectors with interfaces signals

This chapter shortly describes the main Bora components.

Processor Info[edit | edit source]

The Zynq™-7000 family is based on the Xilinx Extensible Processing Platform (EPP) architecture. These products integrate a feature-rich dual-core ARM® Cortex™-A9 based processing system (PS) and 28 nm Xilinx programmable logic (PL) in a single device. The ARM Cortex-A9 CPUs are the heart of the PS and also include on-chip memory, external memory interfaces, and a rich set of peripheral connectivity interfaces. The Zynq-7000 family offers the flexibility and scalability of an FPGA, while providing performance, power, and ease of use typically associated with ASIC and ASSPs. The range of devices in the Zynq-7000 AP SoC family enables designers to target cost-sensitive as well as high-performance applications from a single platform using industry-standard tools. While each device in the Zynq-7000 family contains the same PS, the PL and I/O resources vary between the devices. As a result, the Zynq-7000 AP SoC devices are able to serve a wide range of applications including:

  • Automotive driver assistance, driver information, and infotainment
  • Broadcast camera
  • Industrial motor control, industrial networking, and machine vision
  • IP and Smart camera
  • LTE radio and baseband
  • Medical diagnostics and imaging
  • Multifunction printers
  • Video and night vision equipment

The processors in the PS always boot first, allowing a software centric approach for PL system boot and PL configuration. The PL can be configured as part of the boot process or configured at some point in the future. Additionally, the PL can be completely reconfigured or used with partial, dynamic reconfiguration (PR). PR allows configuration of a portion of the PL. This enables optional design changes such as updating coefficients or time-multiplexing of the PL resources by swapping in new algorithms as needed.

Bora can mount two versions of the Zynq processor. The following table shows a comparison between the processor models, highlighting the differences:

Processor Programmable logic cells LUTs Flip flops Extensible block RAM DSP slices Peak DSP performance
XC7Z010 28K Logic Cells 17600 35200 240 KB 80 58 GMACs
XC7Z020 85K Logic Cells 53200 106400 560 KB 220 158 GMACs
Table: XC7-Z0x0 comparison

On PS side, the following peripherals and devices are connected to MIO signals:

  • Serial NOR fl ash (MIO [6:1])
  • NAND fl ash (MIO [0], [14:2])
  • UART1 (MIO [49:48])
  • I2C temperature sensor (MIO [47:46])
  • I2C MEMS RTC (MIO [47:46])
  • Gigabit Ethernet PHY (MIO [27:16])
  • USBOTG PHY (MIO [39:28])
  • SD/MMC (MIO [45:40])

Since these devices are considered essential, they have been connected to MIO signals in order to make them always functional, even if PL is not programmed. These peripherals represent the default configuration for the BORA SOM, but other configurations can be implemented changing the pin multiplexing

RAM memory bank[edit | edit source]

DDR3 SDRAM memory bank is composed by 2x 16-bit width chips resulting in a 32-bit combined width bank. The following table reports the SDRAM specifications:

CPU connection SDRAM bus
Size min 512 MB
Size max 1 GB
Width 32 bit
Speed 533 MHz

NOR flash bank[edit | edit source]

NOR flash is a Serial Peripheral Interface (SPI) device. By default this device is connected to SPI channel 0 and acts as boot memory. The following table reports the NOR flash specifications:

CPU connection SPI Channel 0
Size min 8 MB
Size max 16 MB
Chip select SPI_CS0n
Bootable Yes

NAND flash bank[edit | edit source]

On board main storage memory is a 8-bit wide NAND flash. By default it is connected to chip select. The following table reports the NAND flash specifications:

CPU connection Static memory controller
Page size 512 byte, 2 kbyte or 4 kbyte
Size min 128 MB
Size max 1 GB
Width 8 bit
Chip select NAND_CS0
Bootable Yes

Integrated FPGA[edit | edit source]

The PL is derived from Xilinx’s 7 Series FPGA technology (Artix™-7 for the 7z010/7z020). The PL is used to extend the functionality to meet specific application requirements. The PL provides many different types of resources including configurable logic blocks (CLBs), port and width configurable block RAM (BRAM), DSP slices with 25 x 18 multiplier, 48-bit accumulator and pre-adder (DSP48E1), a user configurable analog to digital converter (XADC), clock management tiles (CMT), a configuration block with 256b AES for decryption and SHA for authentication, configurable I/Os (with differential signaling capabilities). BORA customers are able to differentiate their product in hardware by customizing their applications using PL.

PL subsystem provides a lot of configurable I/Os, grouped in banks denoted as Bank x (eg Bank 9, Bank 13 etc.). Two types of such banks exist: HR 1 and HP 2. Some of the MIO signals can be routed outside the component via PL subsystem. This technique is called EMIO routing.

Power supply unit[edit | edit source]

Bora, as the other Ultra Line CPU modules, embeds all the elements required for powering the unit, therefore power sequencing is self-contained and simplified. Nevertheless, power must be provided from carrier board, and therefore users should be aware of the ranges power supply can assume as well as all other parameters. For detailed information, please refer to Power Supply Unit page.

CPU module connectors[edit | edit source]

All interface signals Bora provides are routed through three 140 pin 0.6mm pitch stacking connectors (named J1, J2 and J3). The dedicated carrier board must mount the mating connectors and connect the desired peripheral interfaces according to Bora pinout specifications.