The Master
- 20th January 2016, 15:17
Hi, I'm working on a project that requires 4 audio outputs from DACs but I can't find any suitable.
DAC requirements:-
8-bit minimum resolution
16-bits of data per channel max. My PIC only has an 8-byte SPI buffer
3.3V
Each channel must be aligned to an 8-bit boundary
My main concern is the amount of clock cycles the PIC can use communicating with the DACs. Ideally I would like to queue all of the data into the PIC's SPI buffer and exit the interrupt routine.
I can pulse the latch pin at the start of the next interrupt but all of the DACs I've seen require the CS line to be toggled between each message. Even a single DAC with 4 channels requires CS to be toggled 4 times.
I don't have enough clock cycles to wait in the interrupt while the data is sent or to keep jumping in and out of interrupts between each byte.
Does anyone know of a 4 channel DAC that will allow me to simply shift 4 bytes into it? Failing that, I would be happy with 4 x single channel DACs that can be daisy chained so they don't require individual CS control.
I've also considered a hardware solution. Is there such thing as an SPI splitter that would allow me to shift 4 bytes into it and have each byte shifted out of 4 separate data lines?
DAC requirements:-
8-bit minimum resolution
16-bits of data per channel max. My PIC only has an 8-byte SPI buffer
3.3V
Each channel must be aligned to an 8-bit boundary
My main concern is the amount of clock cycles the PIC can use communicating with the DACs. Ideally I would like to queue all of the data into the PIC's SPI buffer and exit the interrupt routine.
I can pulse the latch pin at the start of the next interrupt but all of the DACs I've seen require the CS line to be toggled between each message. Even a single DAC with 4 channels requires CS to be toggled 4 times.
I don't have enough clock cycles to wait in the interrupt while the data is sent or to keep jumping in and out of interrupts between each byte.
Does anyone know of a 4 channel DAC that will allow me to simply shift 4 bytes into it? Failing that, I would be happy with 4 x single channel DACs that can be daisy chained so they don't require individual CS control.
I've also considered a hardware solution. Is there such thing as an SPI splitter that would allow me to shift 4 bytes into it and have each byte shifted out of 4 separate data lines?