2018-08-21 11:33 PM
Looking at the eMMC requirement, it looks like HS-200 mode is limited to 1.8V/1.2V I/O levels. (From STM32H7 MCU Reference manual)
HS200 Bus Speed Mode
The HS200 mode offers:
• CLK frequency up to 200MHz Data rate – up to 200MB/s
• 4 or 8-bits bus width supported
• Signaling levels of 1.8V and 1.2V
So I am assuming that if I want to be able to run in HS200 mode on my design, I need to connect VCCQ(I/O pwr on eMMC) on the eMMC and VDD on the MCU to 1.8V, correct??
But I have other peripherals which should work at 3.3V. so can't provide 1.8V to MCU VDD. I may have to use voltage translator only between MCU and MMC memory. I am not finding voltage translator for MMC which has 8bit data line, 1 command line, 1 reset line,1 clock line and DS line. What is the alternative Solution?
2018-08-22 10:25 AM
What are you're actual band-width requirements here?
Where is the data coming from, where is it going too?
I suppose the alternative would be to use discrete buffers, or bank a secondary transceiver to carry the D4-D7 and have them controlled with the D123_DIR.
If I had 200MBps requirements I'd be looking at a quad core A9 with direct emmc interface..
2018-08-27 12:25 AM
150MBps is the bandwidth requirement. Data is coming from PC to MCU to EMMC and vice versa.
What is that buffer ? Any transceiver part name for 8bit MMC? What is the operation voltage?