Peripheral Board Common Services

In addition to IO pins, each peripheral board connector on the NB2DSK01 motherboard provides pins for the following common services:

JTAG Signals

Both Hard and Soft JTAG signals are wired to the peripheral board connectors, in the same way as for the user board headers – 'User Board A' (HDR1) and 'User Board B' (HDR2). This allows for communications with future peripheral boards that might include JTAG-equipped physical devices (e.g. an FPGA) featuring designs that include Nexus-enabled (Soft) devices. The NanoTalk Controller will only route the Hard and Soft JTAG chains via a peripheral board connector if the signal level on pin 23 of the connector (signal JTAG.DETECT on the motherboard) is Low.

Any of the peripheral board connectors can be excluded from the Soft JTAG chain directly from the firmware-driven GUI on the TFT LCD panel. See TFT LCD Panel - Bypassing JTAG Devices for more information.

Peripheral Board Identification Signal

The NanoTalk Controller uses dedicated ID lines, based on the 1-Wire® serial bus protocol, to verify which peripheral board it is communicating with:

• ONE_WIRE_PB_ID_A – to identify the peripheral board plugged in to the 'PERIPHERAL BOARD A' connector.

• ONE_WIRE_PB_ID_B – to identify the peripheral board plugged in to the 'PERIPHERAL BOARD B' connector.

• ONE_WIRE_PB_ID_C – to identify the peripheral board plugged in to the 'PERIPHERAL BOARD C' connector.

Board identification is achieved through use of a 1-Wire compatible slave memory device located on each peripheral board.

Audio Signals

Line In and Mic In signals from the NB2DSK01's audio input jacks are routed to the peripheral board connectors on the motherboard, appearing as AIN.L, AIN.R and AIN.MIC inputs. These signals provide the audio input to any audio resource (e.g. audio codec) on a plugged-in peripheral board. Line output signals – AOUT.L and AOUT.R – are wired from each peripheral board connector, through to the NB2DSK01's analog mixer circuitry, to be used as input to the motherboard's stereo audio power amplifier. The signals from each connector arrive at the mixer and are distinguished by the connector's position:

• AOUT_PBA.L and AOUT_PBA.R – from the 'PERIPHERAL BOARD A' connector.

• AOUT_PBB.L and AOUT_PBB.R – from the 'PERIPHERAL BOARD B' connector.

• AOUT_PBC.L and AOUT_PBC.R – from the 'PERIPHERAL BOARD C' connector.

I2C Interface

I2C bus signals are provided to each peripheral board connector (I2C.SDA and I2C.SCL) for use with resources possessing an I2C-compatible interface.

SPI Bus Interface

The NanoTalk Controller provides an SPI path to each peripheral board connector, enabling a daughter board FPGA to communicate with/control an SPI based resource resident on a plugged-in peripheral board. Connector signals SPI.DOUT, SPI.DIN, SPI.SCLK, SPI_CS_N0 and SPI_CS_N1 provide this connectivity.

The NanoTalk Controller uses dedicated Chip Select lines to distinguish communication between multiple SPI devices:

• EXTSPI_CSA_N[1..0] – to access devices on a board plugged in to the 'PERIPHERAL BOARD A' connector.

• EXTSPI_CSB_N[1..0] – to access devices on a board plugged in to the 'PERIPHERAL BOARD B' connector.

• EXTSPI_CSC_N[1..0] – to access devices on a board plugged in to the 'PERIPHERAL BOARD C' connector.

1-Wire® Bus Interface

A 1-Wire serial bus interface signal is provided (ONE_WIRE_DB_PB) for use with one or more slave 1-Wire compatible devices located on the peripheral board.

Clocking

Four pins are made available to receive gated clock signals from the NanoTalk Controller. These signals arrive at each connector as three actual clock signals (CLOCKS.CLK0, CLOCKS.CLK1, CLOCKS.CLK2) and a clock enable signal (CLOCKS.EN). The NanoTalk Controller uses dedicated clock signals for each peripheral board, as follows:

• CLK_EXTA[2..0] and CLK_ENA – for a board plugged in to the 'PERIPHERAL BOARD A' connector.

• CLK_EXTB[2..0] and CLK_ENB – for a board plugged in to the 'PERIPHERAL BOARD B' connector.

• CLK_EXTC[2..0] and CLK_ENC – for a board plugged in to the 'PERIPHERAL BOARD C' connector.

Power Signals

Each peripheral board connector provides five power supplies to the docked peripheral board, as well as ground signals. The power supply voltages are 5V, 3.3V, 2.5V, 1.8V and 1.2V.

Current monitoring is in place on all power lines.
 

See Also