Setting the extra pins for the BS2p40???

Comments

• Mike Green Posts: 23,101

  2006-10-04 15:36 edited 2006-10-04 15:36

  Read the section in the Stamp Manual on the AUXIO, MAINIO, and IOTERM commands. Essentially, the BS2p40 has two sets of I/O pins that are numbered 0-15 and these statements switch the Stamp from one set to another.
• Bill Chennault Posts: 1,198

  2006-10-04 16:06 edited 2006-10-04 16:06

  Mike--
  
  Is the concept similar to the dual registers of the old Z80 processor?
  
  --Bill
  
  
  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  You are what you write.
• kuskowski Posts: 17

  2006-10-04 16:53 edited 2006-10-04 16:53

  AWSOME Thanks....
• Mike Green Posts: 23,101

  2006-10-04 17:10 edited 2006-10-04 17:10

  Bill,
  In a way, it's similar. It's a way of compatibly expanding an existing instruction set by adding special instructions to select one of two banks of registers or I/O pins or whatever. All the other instructions work the way they used to, but they work on one set of registers or I/O pins at a time.
  Mike
• Chris Savage Parallax Engineering Posts: 14,406

  2006-10-04 22:30 edited 2006-10-04 22:30

  Bill Chennault said...
  
  Is the concept similar to the dual registers of the old Z80 processor?
  
  

  Bill,
  ·
  ·· The shadow registers on the Z80 could be swapped with an alternate set.· This was usually used in interrupt routines to save having to push everything onto the stack.· This had no effect on the I/O pins or registers related to them.
  ·
  ·· On the BS2p40 when you use MAIN, AUXIO or IOTERM you are changing which bank of I/O pins that subsequent I/O related instructions affect.· I hope this helps.· Take care.
  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  Chris Savage
  Parallax Tech Support
• Bill Chennault Posts: 1,198

  2006-10-05 02:34 edited 2006-10-05 02:34

  Chris--
  
  Yes, that helps a lot. Thanks once again.
  
  --Bill
  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  You are what you write.