Author Topic: iMX RT. New Cortex M7  (Read 18533 times)

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Offline mubes

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Re: iMX RT. New Cortex M7
« Reply #25 on: October 27, 2017, 05:25:52 pm »
For heavy-duty control, the best Cortex-M part is probably the Infineon XMC-4000 series. Very sophisticated and flexible timer logic, etc.

Hmm...don't discount the LPC43 series, and specifically chips like the LPC4367. Those multiple CPUs are very useful indeed. In fairness it's not in the same league as this iMX RT thing though. LPC1549 is much underloved too...

Dave
 

Offline ehughesTopic starter

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Re: iMX RT. New Cortex M7
« Reply #26 on: October 29, 2017, 11:49:13 pm »
I have used the LPC43x series on several projects.    Good chip but the memory segmentation is a real pain. 

The LPC546xxx is a good choice as it has many improvements.    It is the same process technology but uses less power as NXP designed the chip with a new set of IC libraries.        There is more SRAM it is arranged in contiguous region.


I got an early iMX RT board.      The high end LPC line is going to be a tough sell.    This chip is awesome.   It is lower in price,.  Faster and consumes less power.
« Last Edit: October 30, 2017, 02:39:32 am by ehughes »
 

Offline mark03

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Re: iMX RT. New Cortex M7
« Reply #27 on: October 30, 2017, 01:59:40 am »
Any thoughts how this compares with STM32H7, apart from the obvious speed difference?  My initial reaction after looking over the rev 0 datasheet:
  • 600-MHz part only available in 0.65-mm BGA; despite the crowing about four-layer boards, hand-prototyping will not be easy
  • less SRAM than STM32H7, although more of it can be "tightly coupled"; given lack of flash, more would have been nice
  • peripheral set hits a couple of high points, like the SD card controller, but otherwise pretty lackluster
In a part this fast it would have been nice to see some kind of DSP acceleration, besides the rudimentary SIMD in the CM4/CM7 instruction set.  ST has the DFSDM (CIC filters) as well as JPEG engine.  Nothing like that in iMX RT AFAICT.

I wonder which customers drove development of these.  All that horsepower, yet so cost sensitive, why?

Still waiting to be impressed by a 40-nm MCU...
« Last Edit: October 30, 2017, 02:02:08 am by mark03 »
 

Offline ataradov

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Re: iMX RT. New Cortex M7
« Reply #28 on: October 30, 2017, 02:07:03 am »
Any thoughts how this compares with STM32H7, apart from the obvious speed difference?
Looks like the price is a major thing. Also 2x USB HS with integrated PHYs is no small thing.

I don't think the lack of flash is a huge deal. QSPI flash will give very similar performance to internal flash with wait states. And you have a very cheap way to expand your flash size, if needed.

I wonder which customers drove development of these.  All that horsepower, yet so cost sensitive, why?
I'd say all the voice recognition gadgets. It is also a good way to take over M7 market, which is relatively new.
« Last Edit: October 30, 2017, 02:09:28 am by ataradov »
Alex
 
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Online tszaboo

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Re: iMX RT. New Cortex M7
« Reply #29 on: October 30, 2017, 09:35:59 am »
I wonder which customers drove development of these.  All that horsepower, yet so cost sensitive, why?
I'd say all the voice recognition gadgets. It is also a good way to take over M7 market, which is relatively new.
Dont you need a lot of I2S or similar audio interface for that? Like Alexa has 7 microphones inside, so you would need 4 I2S interface. But more is better, since the MEMS michrophones. I guess the lack of flash is simple. They realized, that costumers are going to place a flash anyway, to store images for the display or audio samples to be played.

Quote
The i.MX RT1050 is specifically useful for applications such as:
• Industrial Human Machine Interfaces (HMI)
• Motor Control
• Home Appliance
I wonder which customers drove development of these.  All that horsepower, yet so cost sensitive, why?
It goes into the market gap, where the R series supposed to go. You know, Application, Realtime, Microcontroller = ARM. And then the Cortex R has been forgot. Oh no, wait, there is the Hercules RM57x with very competitive, 38 USD @1K pricing.
 

Offline ali_asadzadeh

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Re: iMX RT. New Cortex M7
« Reply #30 on: October 30, 2017, 02:54:55 pm »
Since volume pricing is around 3$, we can use them for general MCU replacement in most projects, unless ST come back with a cheaper and better 800MHz solution, and I'm sure they will come back on streets again in less than a year! this war is actually so good for us ;) :D

Remember that ST has the 28nm node process! ;D ;D
« Last Edit: October 30, 2017, 02:56:47 pm by ali_asadzadeh »
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Offline ataradov

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Re: iMX RT. New Cortex M7
« Reply #31 on: October 30, 2017, 04:13:13 pm »
Dont you need a lot of I2S or similar audio interface for that?
Yep, and that's why they have FlexIO modules with 32+16 shift registers. I did not go into details on them, but it looks like just the thing for a lot of I/O.

Alex
 

Offline ataradov

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Re: iMX RT. New Cortex M7
« Reply #32 on: October 30, 2017, 04:15:47 pm »
Since volume pricing is around 3$, we can use them for general MCU replacement in most projects
The minimum package size is 100 pins, may be a bit too much for a lot of applications. And there are a lot of Cortex-M0+ to Cortex-M4 MCUs that will fit this price, which may be better suited for applications without the need for the processing power.
Alex
 

Offline technix

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Re: iMX RT. New Cortex M7
« Reply #33 on: October 30, 2017, 07:24:49 pm »
Any thoughts how this compares with STM32H7, apart from the obvious speed difference?  My initial reaction after looking over the rev 0 datasheet:
  • 600-MHz part only available in 0.65-mm BGA; despite the crowing about four-layer boards, hand-prototyping will not be easy
  • less SRAM than STM32H7, although more of it can be "tightly coupled"; given lack of flash, more would have been nice
  • peripheral set hits a couple of high points, like the SD card controller, but otherwise pretty lackluster
In a part this fast it would have been nice to see some kind of DSP acceleration, besides the rudimentary SIMD in the CM4/CM7 instruction set.  ST has the DFSDM (CIC filters) as well as JPEG engine.  Nothing like that in iMX RT AFAICT.

I wonder which customers drove development of these.  All that horsepower, yet so cost sensitive, why?

Still waiting to be impressed by a 40-nm MCU...
I think this chip is intended to be used along with external SDRAM and QSPI, likely 64MB or 128MB of them each. This compensates for the lack of internal RAM anyway, but the board size is increased significantly.
 

Online tszaboo

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Re: iMX RT. New Cortex M7
« Reply #34 on: October 31, 2017, 03:41:06 pm »
Dont you need a lot of I2S or similar audio interface for that?
Yep, and that's why they have FlexIO modules with 32+16 shift registers. I did not go into details on them, but it looks like just the thing for a lot of I/O.
Well, it is certainly not advertised well. Also, the reference manual is 3500 pages, so it would take a while to fully understand what does what. Hence all the white papers and application notes they make for proprietary stuff, like this FlexIO. I guess their technical writers just need to catch up a little bit.

 

Offline ataradov

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Re: iMX RT. New Cortex M7
« Reply #35 on: October 31, 2017, 03:47:10 pm »
I guess their technical writers just need to catch up a little bit.
Yes, even the 3500 page document has a lot of glitches and mistakes. They still sometimes use Verilog notation for numbers :)
Alex
 

Offline Sal Ammoniac

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Re: iMX RT. New Cortex M7
« Reply #36 on: October 31, 2017, 06:13:56 pm »
For heavy-duty control, the best Cortex-M part is probably the Infineon XMC-4000 series. Very sophisticated and flexible timer logic, etc.

Hmm...don't discount the LPC43 series, and specifically chips like the LPC4367. Those multiple CPUs are very useful indeed. In fairness it's not in the same league as this iMX RT thing though. LPC1549 is much underloved too...

I did discount the LPC43 series because its peripherals, especially the ones critical for many control applications, such as the capture/compare units and PWM, are nowhere near as sophisticated and powerful as the ones on the XMC-4000 series.
Complexity is the number-one enemy of high-quality code.
 

Offline technix

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Re: iMX RT. New Cortex M7
« Reply #37 on: November 01, 2017, 04:38:56 am »
I guess their technical writers just need to catch up a little bit.
Yes, even the 3500 page document has a lot of glitches and mistakes. They still sometimes use Verilog notation for numbers :)
Their technical documents leak Veriog a lot... I still remember reading the i.MX7 reference manual and get confused by the clock tree structure, all expressed using graphs exported from Verilog.
 

Offline dav888

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Re: iMX RT. New Cortex M7
« Reply #38 on: December 10, 2017, 03:29:04 pm »
Hi!
iMX RT indeed looks great, but quite surprised that they don't support LPDDR2/3, really hope this is a typo or something they'll add in newer versions.

I've been with Blackfin 52x for many years and lately the 70x (mostly because of the low power-consumption)...
the 70x series added ddr2 which was a big bottle-neck on the 52x series.. (still not LPDDR though..)

Blackfin definitely used to be the goto cpu for doing low-power/battery stuff when they first came out (and kind of still is..!). The drawback might in modern-times be their proprietary tool-chains, lack of good OS/driver support and only closed-source pricey 3rd part drivers... and also I get the feeling that ADI now has their focus on other things.

I think this is where NXP could actually make a huge difference if they just choose the right paths to ensure great support to the onboard hardware peripherals.

Curious to see NXP's plans when it comes to board-support, peripheral drivers and such (especially in the USB host/device space).



Another really weird limitation of the RT series is: Nand FLASH, with ECC handled in software, what?
since most vendors incl. Micron stopped doing On-Die ECC, new SLC NAND's (25nm and future) on the market now requires 25nm: 8-24bit depending on density.. So nothing you want the M7 to crunch due to the lack of hardware ECC in the nand controller...


/David
 

Offline mark03

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Re: iMX RT. New Cortex M7
« Reply #39 on: December 10, 2017, 08:21:29 pm »
I don't think the lack of flash is a huge deal. QSPI flash will give very similar performance to internal flash with wait states. And you have a very cheap way to expand your flash size, if needed.
I recently did a brief survey of available QSPI flash devices and their characteristics, also looking at the emerging 8-bit-wide standards like HyperFlash etc.  What stood out to me the most were the power-consumption numbers.  My recollection from STM32 datasheets where they compare active power with/without flash was that the difference was fairly modest... 10-20%?  whereas most of these external flash devices seem to eat quite a bit more, closer to being on par with the entire MCU active power.  Is this mostly due to the increased capacitance of the external bus versus an internal bus?  In any case, it seems like a significant disadvantage for external flash, power-wise.  Maybe no one else sees these fast M7 parts as suited to low-power applications, but I do, as they use less juice than the application-processor alternative for similar compute performance.

I still think more SRAM is called for.  Even neglecting the internal/external-flash power-consumption differences, just the fact that we are now at 600 MHz means that the flash-vs-SRAM performance gap is growing, and ST already has a competing chip with twice as much SRAM as RT1050.  It looks like NXP intends to fill out this new family, so perhaps the chips coming next year will include some with 1+ Mbits.

Having now skimmed the reference manual a bit more carefully, I must say I am more impressed with the peripheral set than I was before.  Does anyone know what is expected in terms of vendor libraries?  Do NXP/Freescale's peripheral libraries tend to be any good?  or at least better than ST's?

I would still like to see some kind of DSP acceleration peripheral, akin to ST's DFSDM.  Or, if NXP really wants to blow us away, they could provide an optimized software DSP library to replace or re-implement the CMSIS-DSP API.  As other members of this forum have demonstrated, CMSIS-DSP is not very well optimized, and substantial performance gains (2x or better) are possible, but with no off-the-shelf library this is a difficult, time-consuming process.
« Last Edit: December 10, 2017, 08:24:26 pm by mark03 »
 

Offline EarthLord

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Re: iMX RT. New Cortex M7
« Reply #40 on: December 14, 2017, 05:45:40 am »
Quite excited about this beast of a chip. For the power consumption, an important information is the time required to wake up from the various sleep modes. I couldn't find this info scouring the datasheet and the application notes. Any luck for others?
 

Offline alexyzhov

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Re: iMX RT. New Cortex M7
« Reply #41 on: December 14, 2017, 09:08:36 am »
This series is designed by NXP Suzhou Development Team in China, and luckily I know some guys who are responsible to wrote documents about IMXRT, like user guide and application notes.
RT series are just like a kind of redesigns from imx6ull series, after changing the core into M7 from A7, with most peripherals have no change. The 96Kb internal ROM storages a bootloader just acts the same as the bootloader on IMX6 series.
More RT series chip will be released in the following years, like RT with up to 5MB onchip SRAM and 1Ghz M7 core, or some type with high-speed internal flash. Also, these high perfomance type will be fabricated by 28nm node.
They are working on supporting more FLASH devices these days, and more documents about developing IMXRT will be released before 2018.
 

Offline mac.6

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Re: iMX RT. New Cortex M7
« Reply #42 on: December 14, 2017, 03:29:55 pm »
The code part should be reusable, but you will need the include file for the IMX6ULL, given that it's an 1.8MB header file for RT1050 prepare for a lot of work if you do it by hand (it's autogenerated)...
 

Offline nctnico

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Re: iMX RT. New Cortex M7
« Reply #43 on: December 14, 2017, 05:20:33 pm »
RT series are just like a kind of redesigns from imx6ull series, after changing the core into M7 from A7, with most peripherals have no change.
Thanks. That's very good to know. I'm actually working on a design based on 6ULL, but I would like to get rid of Linux. Is there any possibility that I can have access to peripherals of 6ULL (namely, SPDIF, I2C, SPI, Ethernet, USB) with LPCXpress libraries of IMX.RT?
If you want to go bare metal I'd stick with the 6ULL and use the bootloader as the platform. Uboot has support for a lot of peripherals and filesystems. Just no OS like scheduling but if your main application doesn't need that it isn't a problem.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline krho

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Re: iMX RT. New Cortex M7
« Reply #44 on: December 15, 2017, 05:34:11 am »
nuttx?
 

Offline natester

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Re: iMX RT. New Cortex M7
« Reply #45 on: January 03, 2018, 08:19:19 pm »
I’m also thinking about this, anyone know what kind of effort this would be to port to nuttx?
 

Offline dav888

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Re: iMX RT. New Cortex M7
« Reply #46 on: January 04, 2018, 10:34:49 am »
+1

but I'm more leaning towards https://www.zephyrproject.org as the rtos of choice

mainly because:
- it's linux like, similar way of configurating, supports .dts and such
- apache2 licence
- CMSIS
- Linux Foundation behind it + great people involved that used to do kernel drivers for linux in the past
- no IDE "dependency"
- NXP is somehow involved (at least for the Kinetis)

/d
 

Offline drojf

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Re: iMX RT. New Cortex M7
« Reply #47 on: January 08, 2018, 08:36:18 am »
I saw the 'mcuoneclipse' guy posted his experience/a tutorial with the 1050 devboard. Useful if you're interested in purchasing one, or want a well documented walkthrough for setting things up:

https://mcuoneclipse.com/2017/12/16/mcuxpresso-ide-v10-1-0-with-i-mx-rt1052-crossover-processor/#more-22907
 

Offline glenenglish

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Re: iMX RT. New Cortex M7
« Reply #48 on: January 17, 2018, 12:26:48 am »
@Blueskull, If you want an alternative to linux, FreeRTOS is a no brainer.
has lots of goodies for essentially zero interrupt latency processing, jump on return deferred procedure calls etc.
all the good stuff u need for microcontroller things....

and the companion TCPIP stack is rock solid.

I went IMX6ULL in a recent project...couldnt wait for STM32H7.
 
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Offline patacongo

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Re: iMX RT. New Cortex M7
« Reply #49 on: March 07, 2018, 06:15:46 pm »
I am planning the NuttX port now.  I have some other things on my plate so it is a few weeks before I get started.  Maybe some lower cost boards will appear before then?
 


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