Signal Descriptions
Slow FF Q Output
Board label:
SLOW_FF_Q
Grid location:
C1
Description:
This is the Q output signal of the slow
fl
ip-
fl
op. This signal shows metastable behavior frequently.
SPI Bus
Board label:
SPI_SCLK, SPI_SS, SPI_MOSI
Grid location:
D1, G1, H1, H2, H3
Description:
These are the SPI (Serial Peripheral Interface) serial bus signals. (See Figure 1.)
The SPI bus works as follows:
SCLK rising edge clock
Active Low SS
Active High MOSI data
This is the beginning of the mixed signal chain. See the descriptions of these signals: DAC Input, Parallel and DAC Output.
Packets occur approximately every 500
μ
s. The SPI packet contents are transferred to the Parallel DAC Input bus at the end
of the packet. The Parallel DAC Input bus then changes the voltage output of the DAC.
The resulting DAC output is a sine wave with an amplitude 0 to 3 volts, and a period of 31 ms.
The clock rate is a 200 kHz, 0 to 5 volt signal.
SPI Bus (for RF)
Board label:
SPI_CLK, SPI_SS-1, SPI_MOSI-1
Grid location:
B12, C12, D12, H11
Description:
These are the SPI (Serial Peripheral Interface) serial bus signals. (See Figure 1.)
The SPI bus works as follows:
SCLK rising edge clock
Active Low SS
Active High MOSI data
This SPI bus is the control bus for several different parts that control the RF output in the RF based demonstrations.
Spread Spectrum Clock
Board label:
SS_CLOCK
Grid location:
H4
Description:
This is a nominally 98.5 MHz spread spectrum clock with triangular modulation. Use it for demonstrating
timing measurement trends over time.
14
Tektronix MDO Demo 1 Board Instruction Manual
