Casio EA-100 Technical Reference - Manual (Page 7)

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Appendix A: Technical Reference
Other Technical Information
Clock-In Line Operation
A low-going pulse (0-5V) on the External Clock-In line (part of the DIG IN
channel) is used as the external clock.
Data from the DIG IN channel can be read based on the internal sampling
clock, so the External Clock-In line is not necessarily required. Conversely,
the external clock line can be used to control the sampling time for signals on
other channels.
Clock-Out Line Operation
The low pulse width of the external clock line is 1.6 microseconds. Pulse
output can be performed by simply using Command 1 (CHANNEL SETUP)
to specify the DIG OUT channel.
Digital Output Buffer
The digital output buffer (DOB) is a circular buffer that can contain up to 22
data elements. Data elements output from the DOB are 4-bit (TTL 0 to 5V)
binary data nibbles, such as 0 = 0000, 1 = 0001, 2 = 0010, 10 = 1010, 15 =
1111. One data nibble is output on the DIG OUT D0 through D3 lines for
each sample time.
The drive (output current) function for each data nibble and clock is as shown
below.
• Voutput-high > 3.98V (Ioutput-high > –6mA)(negative current flow from
the data analyzer)
• Voutput-low < 0.26V (Ioutput-low < 6mA)(positive current flow from the
data analyzer)
The number of times the DOB contents are output is determined by the number
of data elements defined by Command 1 and the number of samples defined
by Command 3.
Digital Output Buffer Example
Command 1:
{1,6,7,1,3,5,7,9,11,13} 1 = CHANNEL SETUP
6 = DIG OUT
7 = Number of data elements
1 = 0001 (data nibble)
3 = 0011 (data nibble)
5 = 0101 (data nibble)
7 = 0111 (data nibble)
9 = 1001 (data nibble)
11 = 1011 (data nibble)
13 = 1101 (data nibble)