Add clock cycle to SPI

[fastlink30]

#use SPI (MODE=0,FORCE_HW,BITS=8,MSB_FIRST)

this make 8 clk cycle to get/put data on spi interface, i need 1 clk cycle (start condition), send 8 bit (8 clk cycle), and 1 clk cycle (stop condition)

is possible make this or i must make my routine that emulate SPI?

thanks

[temtronic]

simple enough to make your own software SPI but we'd like to know WHAT SPI device you're using that needs start-data-stop format?

That 'format' sounds more like good ol' 'sync'ed RS-232' data(8-n-1) not SPI, though it could also be an I2C device.....

Please tell us what the device is, maybe a link to the datasheet !

hth
jay

[fastlink30]

http://www.ti.com/litv/pdf/slos743f

this device can work with slave select or not, without, need start/stop condition on spi (look 5.9.5.1 on datasheet)

[alan]

Your start condition is when you take SPI ENABLE low and stop condition is when SPI ENABLE is high.

[fastlink30]

I do not use ENABLE signal, to substitute this signal i need 1 clk cycle before and after I have sent bits.
Is required by the chip that i use.

[Ttelmah]

The hardware SPI can't do this.
Software SPI, can be told to use 10 bits, and then you would need to copy the byte to send into a 16bit variable, and rotate this one bit.
You can also do this with the USART (if your chip has one), but on most chips only in half duplex. However the chip does only seem to only ever receive or send, so with an external logic gate this could be made to work.
However using SS, is easier, and likely to be much more reliable (it'll recover if a bit is lost, which the version without SS won't).....

Best Wishes

[asmboy]

i had the misfortune to work with the 7960 a while back

honestly - I ended up using a 40 pin pic , and the PARALLEL method of
control for that part

you will need to bit bang the SPI mode- and since you are implicitly a slave,
( for reading)
also -
you will need to use INTs with a pin on port B to handle the IRQ function..

[fastlink30]

to ttelmah: i have implemented my routine for dedicated SPI, in the next revision of the PCB i want use the SS (make the things more 'standard')

asmboy: why misfortune? INT is already connected with port that handle IRQ function

thanks to all the people

[asmboy]