Parallax BASIC Stamp 2e, Programming Manual

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5: BASIC Stamp Command Reference – SHIFTOUT
BASIC Stamp Programming Manual 2.0c
•
www.parallaxinc.com
•
Page 313
SHIFTOUT
BS1 BS2 BS2e BS2sx BS2p
SHIFTOUT Dpin, Cpin, Mode, [ OutputData {\Bits} {,OutputData {\Bits}…} ]
Function
Shift data out to a synchronous serial device.
•
Dpin
is a variable/constant/expression (0 – 15) that specifies the I/O
pin that will be connected to the synchronous serial device’s data
input. This pin will be set to output mode.
•
Cpin
is a variable/constant/expression (0 – 15) that specifies the I/O
pin that will be connected to the synchronous serial device’s clock
input. This pin will be set to output mode.
• Mode is a variable/constant/expression (0 – 1), or one of two
predefined symbols, that tells SHIFTOUT the order in which data
bits are to be arranged. See Table 5.92 for value and symbol
definitions.
• OutputData is a variable/constant/expression containing the data to
be sent.
• Bits is an optional variable/constant/expression (1 – 16) specifying
how many bits are to be output by SHIFTOUT. If no Bits entry is
given, SHIFTOUT defaults to 8 bits.
Quick Facts
BS2 BS2e BS2sx BS2p
Timing of t
h
, t
l
,
t
a
and t
b
14
µ
s / 46
µ
s 14
µ
s / 46
µ
s 5.6
µ
s / 18
µ
s 5.6
µ
s / 18.8
µ
s
Transmission Rate ~16 kbits/sec ~16 kbits/sec ~42 kbits/sec ~42 kbits/sec
Explanation
SHIFTIN and SHIFTOUT provide an easy method of acquiring data from
synchronous serial devices. Synchronous serial differs from asynchronous
serial (like SERIN and SEROUT) in that the timing of data bits (on a data
line) is specified in relationship to clock pulses (on a clock line). Data bits
may be valid after the rising or falling edge of the clock line. This kind of
serial protocol is commonly used by controller peripherals like ADCs,
DACs, clocks, memory devices, etc.
2
e
2
sx
2
p
2
Table 5.91: SHIFTOUT Quick
Facts.