Numark D2 Director, Service Manual

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SPI Bus
The SPI bus connects the ARM CPU to the Sharc DSP and the PIC microcontroller on the Control
board. The SPI bus is used at power up to load software into the Sharc DSP. For this, the ARM
CPU is the SPI master and the Sharc DSP is the SPI slave. Once this is completed the SPI bus is
then used for communication between the control board microcontroller and the ARM CPU. For
this, the control board micro is the SPI master and the ARM CPU becomes a slave.
Note that a control signal TXD2 is used to tell the control board micro when it is allowed to take
over the SPI bus. TDX2 is and output from the ARM CPU. It is high while the DSP software is
being loaded, and goes low when this is finished to indicate that the control board can become the
SPI master and start communication.
SPI bus signals
Signal Name Function Source
SSCLK SPI clock Driven by ARM while loading DSP software.
Driven by Control board micro after that.
SSFRM SPI frame (frames each byte) Note used when loading DSP software. Driven
by control board micro after that.
SSTX SPI data transmit Driven by ARM while loading DSP software.
Driven by Control board micro after that.
SSRX SPI data receive Driven by SHARC while loading DSP software.
Driven by ARM board micro after that.
GPIO14 SPIDS for Sharc DSP (low
while loading DSP S/W) Driven by ARM
I2S audio signals
I2S audio interfaces are provided between the ARM CPU and the DSP. Audio can be sent in both
directions, though in the NH00 only the outputs from the ARM are used. The DSP is the I2S master
and the ARM is a slave. All audio on this interface is transmitted at a sample rate of 176.4kHz.
Signal Name Function Source
ARM-BCLK I2S bit clock (11.2896MHz) DSP
ARM-MCLK I2S master clock (not used because ARM does
not need master clock) DSP
ARM-LRCLK I2S word clock (176.4kHz) DSP
ARM-SIN0 I2S data in channel 0 (not used in NH00) DSP
ARM-SIN1 I2S data in channel 1 (not used in NH00) DSP
ARM-SOUT0 I2S data out channel 0 (deck A) ARM
ARM-SOUT1 I2S data out channel 1 (deck B) ARM
ARM-SOUT2 I2S data out channel 2 (not used in NH00) ARM
USB
The ARM CPU provides 3 full speed (12Mbit/s) USB host ports. Each port uses a differential pair
of signals; USBP0/USBM0, USBP1/USBM1 and USBP2/USBM2 are the 3 ports.
I2C
An I2C port is provided; SDA (data) and SCL (clock). The ARM is the I2C master.
This is used to configure the audio codec. It is also connected to the RTC chip although at present
the RTC chip is never communicated with.