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Hi Christof, I think the Teensy4.1 is slower than the Pi5 as it is a different processor. If I emulate without PSRAM, it is hardly slower. I only tested with RAM2 though, not the faster RAM1 as I don't have enough memory free for that. My...

Hi, I wrote a PDP-11/70 emulator that runs on lots of systems, especially on the Teensy 4.1. The plus of the teensy4.1 is that it has Ethernet and plenty PSRAM (altough only 4 MB of that is required). It is also very fast: booting an emulated...

From the start: Put a tiny blob of solder on one corner pad Using tweezers position the PSRAM as best you can Reflow just that corner pad Solder the opposite corner pad; you can make minor position adjustments with the tweezers, the legs are...

The flash memory has a 4 bit data path at approx 100 MHz. It's cached by a pair of 32K Cortex M7 caches (one for data access as in this case, the other for instruction fetches), so you only suffer the slow 50 Mbyte/sec speed for cache misses...

However, you can use the nice and convenient initialization with inline strings and only a single PROGMEM if you define your struct to hold the actual character data rather than the address of a string located elsewhere. By declaring your struct...

To get it all into flash memory only including all the string data, unfortunately an awkward syntax is needed with each string defined separately. If you define the strings inline, even though the cmd_pairs[] array is defined with PROGMEM, only...

Because for Teensy 4.x all data defaults to RAM1 unless you specify otherwise.

You want PROGMEM for const data in flash, FLASHMEM is for code/functions. Since your structs are actually holding pointers to string literals, those will need to be stored separately in flash; F() is documented as intended for this but does not...

Ok fixed and all memory tests passed! I'm surprised as it took me a long time to solder so the chip must've gotten really hot.

Haha oh dear now I can see why the test-program said it has 0 MB of PSRAM :) | Learned a few things already: * glue the chip to the board first (at the sides) * glue the teensy to the table first * don't breath during soldering

Oh right, the 'FLASHMEM' and 'DMAMEM' keywords. Odd: I expected const-data to be retrieved directly from flash. Is that technically not possible? Or too slow? I've now put it in DMAMEM.

Hi, I've got this structure: struct cmd_pair { const char *const command; const char *const parameters; const char *const descr; const cmd_func_t func; enum { par_yes, par_no...

Is it also possible to somehow make FLASHMEM the default for the functions of a certain program?

Sometimes, when I programmed a bug, the teensy 4.1 locks up. No trap, no messages, only a blinking led (2 flashes then nothing then 2 flashes, etc) When it is powercycled, no message (of course?) appears from CrashReport (as it was powercycled)...

https://eckstein-shop.de/PJRC-Teensy-41 https://www.berrybase.de/psram-chip-fuer-teensy-4.1

16MB PSRAM chips are now in stock in the UK from: https://thepihut.com/products/16mb-psram-chip-for-teensy-4-1 I just bought 6 for 3 boards.

It's much easier if you solder the chip before adding header pins or wires. Best to run the memory test program to confirm it's really working before adding other stuff that blocks easy access to the chip.

That's without PSRAM. I decided to order a few of those spi-ram chips and see what my soldering-skills are worth.

Hi, Does anyone know a webshop that sells teensy 4.1 with ps-ram (and Ethernet) to Europe? (the Netherlands to be precise) I found only one webshop, but that was usa only (https://protosupplies.com/).

Ah yeah, that works as well. Thanks!

Hello, If I'm right, the teensy 4.1 sdk does not support e.g. %zu (for size_t) and others in sprintf. Is there a solution for that that does not involve an #ifdef for each invocation?

Eventually found that freertos allocates everything from RAM1 which then fills up quickly. By carefully reducing stacksizes and even succeeding in removing a task altogether the emulator now seems to work. Still need to obtain a teensy 4.1 with...

Ok so it als runs somewhat, quite a few modifications have to be done to make it fully work. The good news: it is around 5.5x faster compared to an esp32-s3! Unfortunately 512 kB ram is not enough to run an emulated BSD 2.11 in. So I'm going to...

Ehm https://forum.pjrc.com/index.php?threads/linker-error-embedding-lua-on-a-teensy-4-1.70573/#post-339912 "een ezel stoot zich geen twee keer aan dezelfde steen" as we say in Dutch.

Hello, I'm porting a esp32 project to teensy 4.1 as I expect a better performance (like other migrations did). Now everything compiles sofar but one thing keeps pestering me...