Datasheet

National Semiconductor Page 6 www.national.com
2 System Functionality
2.1 System Block Diagram
Micro-Controller
Atmel SAM3U
(U1)
>
Level Shifters
USB
Connector
(J8)
LP3910
Multiple
Supply
Switching
Regulator
(U11)
Boost
Regulator
(U12)
Filter
12MHZ
Xtal
Debug
Connector(J9)
SD Card
(J7)
Ext
Pwr
(J10)
Input
Protection
32kHZ
Xtal
8MBx16
PSRAM
(U4)
JTAG
(J2)
Static Mem intrfc
GPIO
GPSI 32
Connector
(J6)
<
Level Shifters
GPSI A GPSI A
GPSI A
GPSI A
Pins 1,3,7,8,16
Pins 23-30
Pin 15
Pin 13
Pin 14
Pin 11
GPSI B
Pins 5,6,9
VDDIO
Debug
Connector(J1)
3.3V_DUT
I2C(SCL)
DUT 3.3V
DUT 5V
3.3V_DUT
I2C(SDA)
Pin 12
DUT 5V
Spartan 6
XC6SLX16
(U5)
3.3V
IO Voltage
3.3V
NBS0-1
D15-0
NCS0
NWR
NRD
A23-1
NCS2
NCS3/FPGA_CFG
USB
USB
5V
1.8V
1.2V
DUT 3.3V
DEBUG
(J4)
I2C
DUT3.3V_EN
DUT3.3V_EN
Figure 2 - SPIO-4 System Block Diagram
2.2 General System Overview
The SPIO-4 board is controlled via the Atmel SAM3U micro-controller that is based on an ARM M3, 32-bit
embedded core. It provides the interface to the computer via a USB interface. The DUT board interfaces
to the SPIO-4 via J6, the GPSI-16/32 connector. The GPSI-16/32 interface provides control, data and
power to the DUT board. The interfaces on the GPSI-32 can be I2C, SPI with multiple-device capability,
and parallel interface. The dedicated I2C interface on the GPSI-16/32 is primarily for control and DUT
identification, while the dedicated SPI interface may be used for control or for data transfer. The I2C
interface is derived from the peripheral of the microcontroller. As there can be a wide variety of SPI
requirements for DUTs, the SPI interface can be provided via a processor peripheral and over the
dedicated SPI lines as shown in this document, or the on-board Xilinx Spartan XC6SLX16 FPGA may be
used. In fact, the FPGA may be used to implement DUT interfaces other than SPI – such as high-speed
I2C for data purposes and parallel data-plus-clock interfaces. A large external SRAM 8Mx16 is connected
to both the processor and the FPGA which is used to provide additional device data storage in case the
microcontroller’s or FPGA’s on-board memory is insufficient.
Power is provided to the system via the USB cable, or external power jack. A switching regulator is used
to produce the 3.3 volt supply required by the microcontroller and GPSI-32 devices. A boost regulator
creates the regulated 5 volt supply required by the devices interfaced to the GPSI-32 connector.