Thanks, Mike. I appreciate your help. ----- Original Message ----- From: "Michael Rigby-Jones" To: "Microcontroller discussion list - Public." Sent: Friday, July 27, 2007 5:21 AM Subject: RE: [EE] Software SPI > > >>-----Original Message----- >>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] >>On Behalf Of Rich >>Sent: 27 July 2007 02:27 >>To: Microcontroller discussion list - Public. >>Subject: [EE] Software SPI >> >> >>Has anyone created a software SPI? > > SPI is trivial to bit bang compared with e.g. I2C. However, note that > there are four possible timing/polarity variations with SPI, and most > peripherals only support one. The data can be clocked on a positive or > negative edge, and on a trailing or leading egde so you have to make sure > you set up the data at the right point. The PIC datasheets usualy have a > diagram explaining this in the MSSP section. > > For the highest possible speed, don't use a loop but clock out each 8 bits > with separate instructions (i.e. unroll the loop). This has only a small > code size overhead but can give a good improvement in bit rate. > > Regards > > Mike > > ======================================================================= > This e-mail is intended for the person it is addressed to only. The > information contained in it may be confidential and/or protected by > law. If you are not the intended recipient of this message, you must > not make any use of this information, or copy or show it to any > person. Please contact us immediately to tell us that you have > received this e-mail, and return the original to us. Any use, > forwarding, printing or copying of this message is strictly prohibited. > No part of this message can be considered a request for goods or > services. > ======================================================================= > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist