Mach-DSP User’s Manual
Document Number: MACH-DSP-9021
Page 11
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3.2b
3.3-volt TTL-level Digital Command Input with Status Feedback
The Digital Command Input and Status feedback signals (and a few unrelated signals)
are provided on unpopulated 100-mil-spaced through-hole pads located directly to the
right of the Status / Control connector. Table 3.2b below describes the signals:
Table 3.2b: Digital Command Input
Pin
Function
1
Ground (pin 1 indicated with square pad)
2
(reserved “Power Amp Enable active low”)
3
Serial Port Y-axis data input (Position Feedback output for FB4)
4
Serial Port X-axis data input (XY-axis data input for FB4)
5
Serial Port Frame Sync input
6
Serial Port Clock input
7
(reserved “PWM power amp clock”)
8
(reserved “PWM power amp clock”)
Signal description
As implied by Table 3.2b above, Digital Command Input communication is presently
facilitated through a multi-wire serial interface consisting of Clock, Frame Sync, one or
two axis inputs, and an optional Status feedback output. The XY2-100 protocol uses
separate inputs for X-axis data and Y-axis data. The FB4 protocol uses a single input
for both X and Y data, and uses a single output for Position Feedback.
Voltage Levels
The digital signals found on these unpopulated through-hole pads use 3.3V TTL signal
levels. These signals may be connected directly to other 3.3V microprocessor-based
equipment that is located physically close to the Mach-DSP. For equipment located
farther (such as typical equipment that uses the XY2-100 standard), an optional
daughterboard (described later in this manual) can be fitted to the Mach-DSP, which
adapts RS-422 differential signals to the 3.3V signal levels.
Additional unpopulated through-hole pins nearby
In addition to the 8 unpopulated through-hole pads mentioned above, there may be
additional unpopulated pads nearby, such as 5 or 6 pads, depending on the date of
manufacture. Those are reserved for future use and you should not connect to them.
Available cables
Digikey part numbers 1528-1964-ND and 1528-1967-ND may be soldered to those
unpopulated pads, and thus used to connect your digital signals to the Mach-DSP.
