SHIFTIN has been kept as a compatable function with PBASIC.  It can be used for devices that are not covered by SPI, I2C or 1-Wire. Data is shifted in on in_pin, and a positive clock is sent on clk_pin for each bit.

While most other hardware functions use bytes, SHIFTIN is oriented for bit control.  The length of each variable defines the number of bits that will be shifted out (2 - 32).  For each word bitLengths bits will be shifted in.

• Mode = 0   data is shifted in MSB first, and sampling starts before the first clock pulse
  
• Mode = 1   data is shifted in LSB first, and sampling starts before the first clock pulse
  
• Mode = 2   data is shifted in MSB first, and sampling starts before the second clock pulse
  
• Mode = 3   data is shifted in LSB first, and sampling starts before the second clock pulse

SHIFTIN fills the integer array wordList .  cnt integers will be shifted in.

Data is shifted in at 600 Kbits/sec.

• SHIFTOUT
  
• SPIIN