How to convert SPI to parallel address?

[winglj]

parallel address

Hi, I have a silly question about the microcontroller SPI interface.

Suppose there is a SPI signal with first 4-bit as address, and last 8-bit as a DAC code. I am wondering whether there are any peripheral devices that can convert this 12-bit SPI to a parallel 4-bit address code, and a analog signal from the 8-bit content?

Thanks.

 

[Kurenai_ryu]

spi parallel

maybe using some shift registers? a couple of 4094 can shift the data and then you can strobe it to the dac... or a 74HC164 with or without a latch register..

just an idea...

 

[FvM]

convert spi

Generally, SPI, is supposed to use multiple of 8 bits for the frame length. So it would typically 16 bit in total for 12 bit payload.

Shiftregisters as 74HC595 or CD4094 can be used to decode SPI to parallel.

 

[vahidnoori]

hi.
is there any body that have schematic of spi to parallel converter???

 

[betwixt]

I think they just told you one.
SPI = Serial Peripheral Interface, all you need is a serial in, parallel out shift register like the ones mentioned. There is no coding involved, the SPI clock moves the SPI data along the shift register and the select signal tells you when it's ready to use. There are no easily available 4-bit shift registers but if you daisy chain two 8-bit ones it will work exactly the same, you just ignore the extra four bits. It is at most a two IC solution with no other components required so a schematic isn't worth drawing. I'm pretty sure there are examples of daisy chaining more than one shift register in their data sheets.

Brian.

 

[dwcookiemonster]

if you are using shift register, you need multiple of 8 bit clock signal, no matter you're filling 4-bit for addressing in first 8-bit frame and next 8-bit frame for data. it means 16-bit data length at a time. you can use two shift register in chain to separate it. 74595 series is good choice with its storage register.
or if you mind device interchain in single serial bus, try to consider I2C.