How to use Bit order Alternatively in SPI communication Protocol

[gain]

HI,

I want to configure HT1632 LED driver using SPI communication protocol

for that i should send commands LSB to MSB

immediately data should go MSB to LSB

My question is how to change bitorder after  transfer commands through nrf_drv_spi_transfer()?

kindly provide solution

[awneil]

Have you checked the Product Specification and SDK documentation? 

What do they tell you?

[gain]

Hello,

Thanks for the replay

my question for changing the  bit order  should i initialize spi again for that particular data or any other method 

after change bit order it will comeback to initial position(i.e MSB to LSB)

[awneil]

gain said:

Thanks for the replay

* reply

gain said:

for changing the  bit order

You mean you watt to change the bit order in the middle of a transaction?

That would be extremely unusual!

Are you sure you really need to do that?

http://www.catb.org/esr/faqs/smart-questions.html#goal

But your first step must still be to study the Product Specification and SDK documentation - they will tell you if the chip supports programmable bit order at all and, if so, how to access the facility via the SDK.

Having established whether it's possible to configure it at all, you can then investigate whether it can be changed in the middle of a transaction.

[gain]

Thanks for providing link 

I will correct it.

I need to send in signgle transaction  COMMAND,ADDRESS AND DATA. 

Task is to send command and address MSB first and DATA is LSB first 

How can i tackle this problem 

[awneil]

gain said:

HT1632 LED driver

This: https://cdn-shop.adafruit.com/datasheets/ht1632cv120.pdf

In particular, this:

Which does, indeed, have the address going A6...downwards but data going D0...upwards !!

 

What were they thinking?!

But does it really matter?

Think about it: Unless you're actually doing arithmetic with it, the bit ordering doesn't matter.

So you can just create these as bit patterns - such that the bits will be in the right order when they arrive at the HT1632.

In particular, the "data" is just a bitmap where 1 bit corresponds to 1 LED - so it makes no difference whether you call the left-most bit "most significant" or "least significant".

Those bits have no "place value" - therefore, no "significance" in the arithmetic sense