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doceme / py-spidev

MIT License
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Delay does not delay in between blocks #20

Closed dhhagan closed 9 years ago

dhhagan commented 9 years ago

It appears that delay_usec delays the chip select deactivation, but nothing else. When sending multiple bytes, there is not delay in between the bytes which is how I interpret the purpose of delay_usec. Is that even the correct interpretation? See image below: Sent two bytes with delay_usec = 9000

issues1

doceme commented 9 years ago

Unfortunately, I think delay_usec is only designed to delay between transfers, but not between each byte. See https://groups.google.com/forum/#!topic/linux-sunxi/61CJ4tFaGMQ.

dany0792 commented 5 years ago

Hi, I use your project(spidev 3.4) to make a communication between (personal development board) and (ASUS Tinker Board S). I use xfer2 function to read spi data on ASUS Board from my board. So i want to add a delay_usec in between blocks, I found the delay_usec in the spi.xfer2 but it is not working for me. I have tried several ways to add this delay, but I didn't succeed. Some of my attempts I used are:

spi = spidev.SpiDev()
spi.open(2,0)
spi.mode = 1
#spi.max_speed_hz = 250000
spiResp = spi.xfer2([0, 1, 2, 3], 250000, 1000, 8)

or:

spiResp = spi.xfer2([1])
spiData = range(spiResp[0])
spiResp = spi.xfer2(spiData, 250000, 1000)

Please, help me with that ... Thank you!