Just got my new 4 layer board and 2 layer daughter cards. I need to make a new analogue IO board to but will have to use
my old one for now.
I decided to be brave and add the stm32f7 micro and programmer on the underside. I also included DRAM !
I'm not sure I'll use the JTAG or not. I have a micro usb port hooked up to an STM style serial programmer.
There should be 2 x uSD cards slots but I didn't appear to have DMA capable pins left on the micro to accommodate that.
I have broken all the spare micro pins out so maybe i will find a way to make the redundant file storage work.
I didn't bother with a usb host controller to simplify the design.
I kept all the parts to 0603 and avoided BGA
The DSP and QSPI flash are QFN style though.
I'm using a 10 channel fan out clock buffer U5 for 24.576mhz. the ARM micro can generate this but using the external clock
I can hopefully keep clock jitter to a minimum.
As you can probably see in pic there a ton of vias ! The DRAM chip is under the micro and there seams to be no good
way to wire up RAM to a stm32f7 !
Each trace has only 1 via from micro to dram. Its not running to fast so hopefully it will work.
The Daughter boards are spit plane and analogue power / GND will come from the analogue connector IO side
I don't really need 32 channels of balanced analogue audio IO !
I may well make BUSIO_B a digital IO board !
I was thinking of AES3 or maybe even something like DANTE
There's a bluetooth module header and SPI header that runs to the analogue board for digital gain etc.
I've ordered the parts. the NOR flash qspi chip was near impossible to get , I got some samples on way. 20 week lead time!
Might need to try and change that part to something less difficult to obtain on the next revision.
I should have enough power for all the IC's including the digital side of the ADC's and DAC's.
Lets hope I haven't made to many mistakes and its usable :) I'll be happy to bin the old proto board that didn't even have
power or ground planes :)