Enhance: Add instructions for SPI

Question

Enhance: Add instructions for SPI

mikaelpatel opened this issue 9 years ago · 5 comments

SPI transfer function; spi-transfer ( data0 -- data1 ).

cs low
data spi-transfer 
cs high

Answer 1 · 2016-02-27T19:31:20.000Z

It occurs that you are running out of single characters. (So far you have done an admirable job of assigning them.) '$' is not taken, but perhaps you need to use an escape character. Possibly $ could represent 'serial', so $S might be SPI, $I be I2C, $1 be Serial 1, etc. Also possibly $> and $< could be serial in and out.

Answer 2 · 2016-02-27T19:45:56.000Z

It occurs to me that these buses are bidirectional, so ine needs two commands each. Perhaps noncapitalized and capitalized letters? Eg $s and $S for SPI.

( You have done such a good job so far, please take these as off-the-top suggestions.)

Answer 3 · 2016-02-27T20:30:02.000Z

Using $ as a prefix to extend the opcode is a great idea. I have used that before in the vfm project. That is an advanced forth virtual machine. Unfortunately not yet ported to the Arduino. The Shell is a short-cut :). Anyway a virtual member function that is called for $ prefix opcodes is a neat way to extend the Shell opcodes. That goes on the todo list.

Answer 4 · 2016-02-28T00:14:55.000Z

Added a simple sketch to demonstrate how to handle extended instructions (trap). Please see commit 430b91e.

Answer 5 · 2016-02-28T01:52:01.000Z

So, SPI write might be:
[ 1,2,3,4] $S
Leaving 4 read values and n on stack?
5 6 7 8 4

Xn...X0 n --- Yn...Y0 n