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I meant 16 bytes + the 5 bytes overhead (1 com + 3 add + 1 wait) but still below 4us total (2.4us at 70MHz if I am correct)

Thanks a lot for the spec hidden detail but by luck the current page size in the driver is 16 bytes.
So it reads max 16bytes in an SPI transaction (always from a 16 Bytes page boundary, at 0, 16,...

Code is within every emulator but I created a separate project at:
https://github.com/Jean-MarcHarvengt/psramips6404

More emulators ported to the derived project
Recently added PC engine, Gameboy, Sega Master System, Megadrive and AtariST using external a PSRAM module.....

There are many on PC. I used Speccy the most known. Also nice FPGA projects.

In meanwhile, I could ported more emulators to the Teensy 4.0 using a PSRAM module.

Recently added PC engine,...

More emulators using the PSRAM module on the Teensy 4.0.
Next to PC engine now Gameboy, Sega Master System, Megadrive and AtariST are using it.
I had to struggle a week with the SW before figuring...

It will be a challenge as USB stack takes about 50KBytes. Will have to gain 50k ram for the emulator but nice project for Christmas holidays...

In the meanwhile more emulators ported to Teensy4....

Here are few pictures of the T4+PSRAM piggy back and the PCB breaking board I created for the emulation project
18157
18158
With both the ILI9341 + the SD card (from the ILI) on SPI0, I cannot go...

Hi,

I tried on another setup where only the ILI9341 (2.2") was connected on SPI0.
I can reach 100MHz clock in DMA and I also did not notice any issue without DMA.
This w-e I will create a PCB...

As I also have the SD card on the same bus as the display, the load is probably slightly different.

Thanks for the tip.
My understanding from the post is that the ILI9341 was running at about 40MHz with the old limit.

With the change I can set it up to 60MHz for the display and same for the...

Should be doable. With a bit more memory, USB midi could be used. I will put it on my TODO list. Resolution might be the biggest problem.

if I run the tool of Kurt I get:

FlexRAM section ITCM+DTCM = 512 KB
Config : aaaaaaff
ITCM : 110976 B (84.67% of 128 KB)
DTCM : 377536 B (96.01% of 384 KB)
Available for Stack:...

Now added PC Engine support in MCUME
https://youtu.be/Ot9RgDMqdF4

I am not an expert of SMD soldering but I managed to solder it without any problem. I use flux. It helps a lot for me as I don't have specific equipment for SMD. No issue with MSL also.

The PC...

I would like to share my first experience using PSRAM (SPI RAM) on the Teensy 4.0.

Few weeks ago I decided to port one more emulator core to my MCUME project....

I bought them at Electrodragon.
https://www.electrodragon.com/product/2pcs-ipus-ips6404-iot-ram/
The SMD package 3.3v version.
I am from Belgium. It took 2-3 weeks.
I ordered 8 and I got...

What exactly happens if you compile for smallest code size? Is all code remaining in Flash? So is it like every function was labeled PROGMEM? It typically free up RAM for me.

Hi Paul,
Talking about FlexSPI, anyone already tried to mmap another SPI device as PSRAM, in another region. For the SPI flash, is every block/page read cached in the FASTRUN too?

I am currently experimenting with PSRAM on the Teensy 4.0.

I finally got an IPS6404 (8MB RAM) working on the SPI2 bus of the Teensy4.0.
Speed can still be improved but I am not using DMA transfer...

This is indeed the Arm7 procedure working on the T3.6 but not working on the T4.
No progress so far.

For the teensy 5.0 for sure 2 full SPI busses next to the on board uSD. One of the SPI could be pre-wired to smd pads where a psram could be optionally soldered.

I would reconsider the flash...

Not tried on the T3.5 (I don't have one) but it now works on more platforms including the cheap and great Teensy4.0 allowing AtariST emulation

https://github.com/Jean-MarcHarvengt/MCUME/

Great! Mjs513 posted some info in the Teensy4 software restart thread. It seems that every attempt to restart the T4 results in a shutdown? Not clear what the reason is and if there is already a...

Same behaviour as with wdog sample of tonton81 I had posted the question yesterday in the teensy beta thread, Tonton81 did react and will have a look later. Thanks to all.

Some correction, I see the callback message but no reset occurs (monitor output greyed out)

also you have to adapt the code for the macro WDOG_WCR_WT as below I guess else it does not compile...

Happy that you reacted and sorry for the confusion.

Again, my gall is to generate a reset of the T4 by software (reboot the same flashed image)
I indeed tried your example on the Teensy4.0. I use...

Anyone know how to trigger a reset of the Teensy4 in software?
I tried WDOG but not clear where the WDOG would be locked during startup code (I don't see in the code)

I also tried the arm v7...

SCB_AIRCR = 0x5FA0004;
while (true) {
;
}
Also not working on the T4

I asso don't see why I would unlock the WDOG.
I don't see it locked in startup code?

Also tried below procedure but no luck (see 1060 manual)

*(volatile uint32_t *)0x400BC004 = 0xD928C520;
while((*(volatile uint32_t *)0x400BC000 & (1UL<<11) )==0);
*(volatile uint32_t...

I saw it also yesterday by accident.
That does not work for me. The project is blocking the T4.
I think it was developed for the T4beta1 using the 1052

Is there a way to trigger a reboot of the teensy 4.0 from the code? E.g. using watchdog? Anyone implemented it already?

I just published the video today:

https://youtu.be/q_BFhx5OfPc
https://youtu.be/MSNT9EDy8uM

Visit the project here:
https://github.com/Jean-MarcHarvengt/teensyMAME

Sound yet to come...

Source code published
https://github.com/Jean-MarcHarvengt/teensyMAME
https://youtu.be/q_BFhx5OfPc
https://youtu.be/MSNT9EDy8uM

Hi,

You can find the example that blocks the Teensy4.0 at startup (needs a button press) in my MAME port git project.

https://github.com/Jean-MarcHarvengt/teensyMAME

load teensyMAMEClassic2...

hi Mike,
About the SPI display you should use DMA mode on the T4 (and T3.6)
There are various versions on the T4 forum but the one you can find in the MCUME project is derived from the one of Frank...

I can provide you a sample but indeed, you could only warn the user as the stack usage for the remaining memory will be application dependent.

That makes sense. Paul once indicated that the second 512KB was almost available for malloc at the exception of a library/driver using a bit of DMAMEM.
My experience is that as soon an application...

no, don't dream ;-)
Only early 80ths classics are working (dig dug, moon patrol, pacman...). Even Xevious is problematic.
The main issue is that Mame expands all GFXs to min 8bits per pixel in RAM...

Hi Mike,
So you are actually the person that did the initial Atmega port but also the T3.6 with spi RAM. I indeed started from that version. I have a greetings section at the bottom of the page, I...

https://github.com/Jean-MarcHarvengt...ster/README.md

Here you can find few emulators that I ported to the teensy4. 8086 was one of them. You can try changing the HDD image for this particular...

Initial port available soon.
Only very basic classics as pacman, galaxian, galaga... (more fancy classics will require some serious redesign dur to lack of memory)
No sound yet
Picture will be...

MCUME multi-systems emulator has been upgraded to support Teensy4.0 and ST7789 Display.
Now with Atari 520ST support (Motorola 68k core running full speed!)...

As promised, MCUME multi systems emulator updated to Teensy4.0 and ST7789.
Now with Atari 520ST support (Motorola 68k core running full speed!)...

MQS sound is now ok. With pin10 mono (not using pin 12). I am still interested to know how to disable fully MQS on pin 12 in case I would use MISO one day.
I now soldered the SD using SDIO iso SPI....

Thanks for the tip. Mono sound is is enough. If I could use pin 10 only for audio (CS can be whatever pin) and disable MQS on pin 11.
As soon the SPI init is called, MQS sound stops. I guess I need...

Thank you Manitou! I never noticed it was on the card. It works also for me with the guitar sample. I thought it was on pin 2 (out2). You know if it can be reconfigured somewhere else. 10 and 12 are...

Hi Frank,

Is the MQS output still supported in the Audio library for the T4?
On what pin does it output sound? I tried pin2 with 100uF (+ at pin 2 side), speaker in series to ground but I hear...

Sorry, just saw this link now:
https://www.pjrc.com/breakout-board-for-teensy-4-0/
Thanks Paul.