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My instructions were not entirely clear. Those 4 UART pins must remain out of the socket so that they are disconnected from the Sorcerer's cassette circuitry. For the same reason, simply soldering to the main board underside won't work reliably. That causes the Teensy outputs to fight the...

Shame that Teensy 3.5 is out of stock everywhere until next year. This project could be adapted to T3.2 with an SD card shield, but that might not be available either. Because we are interfacing with 5V TTL here, we need the 5V tolerance of those two Teensys. Others won't work.

Cool! Thanks.

I traced out the part of the LED circuit visible on the board. I'm not sure there are 4 LEDs nor what V+ voltage is. I measured the voltage across the 8.2 Ohm resistor as 0.40 V, so the LED current is 49 mA. I touched other resistors parallel to the 8.2 and the backlight got brighter and the...

I see now someone else has branched the library and made the changes: https://github.com/mjs513/NXPMotionSense Thanks!

I found two workarounds. First, just #define private public which is naughty. Second, make local copies of the functions bool MPL3115_read(int32_t *altitude, int16_t *temperature) static bool read_regs(uint8_t i2c, uint8_t addr, uint8_t *data, uint8_t num) static bool read_regs(uint8_t i2c...

I see a function in the NXPMotionSense library to read altitude from the pressure sensor, but it's private: private: void update(); bool FXOS8700_begin(); bool FXAS21002_begin(); bool MPL3115_begin(); bool FXOS8700_read(int16_t *data); bool FXAS21002_read(int16_t *data); bool...

Can't find it now but I remember someone posted a schematic clip with a transistor driver for the blacklight. That would make sense if 3.8 mA is the base current, so I'm not measuring the LED current.

Oops, missed a decimal point! It's only 3.8 mA. I also tried 69 ohms and got .26 V, and 43 ohms gave .17 V. That's still just 3.8 mA and I saw no change in brightness. Wow, does the board have a current regulator?

I got the V1.2 board and used the recommended 100 Ohms to Vin. I measure 0.38 V drop at 4.84 V, so 38 mA to the backlight LEDs. Are the LEDs in series or parallel? Do we know their current limit? A little more brightness would be nice for outdoor viewing.

My app includes a filled rect which must move left and right one pixel at a time. The simplistic way to move it is to call fillRect with background color and call it again with new coordinates and foreground color. That is slow and causes flicker. A better way is to redraw only the pixels which...

Also, is there any plan to CE certify Teensy LC?

Thank you very much for the thoughtful reply.

I need a 5V digital output and I see Teensy 2.0 is scheduled to be discontinued next year. How much longer is Teensy LC expected to be manufactured?

Here are the source files. Not pretty, but commented at least, so you can follow it. It's built on Arduino 1.8.13, Teensyduino 1.53, and SDFAT library 1.1.4.

That's me. Saw your post there. Sorry, didn't connect. Here's the Z80 side of the code, not quite pretty: const char trmld[] = { // Z80 code TRMLD: 0x3E,0x0C, //TL LD A,FF 0xCD,0x1B,0xE0, // CALL VIDEO clear screen 0x06,0x0E, // LD B,14 0x3E,0x0A, //LL LD A,LF...

Thanks! Yes, I wrote the Z80 code which works as described above: "In operation, Teensy repeatedly transmits a small piece of Z80 code, the terminal/loader, along with the required 5-second header. When the user enters LOG (LOad and Go) the Sorcerer runs the code and signals Teensy to send a...

This simulator implements the Exidy tape file format, so it's not directly portable to other systems. However, it could be adapted. I don't know C64 nor Spectrum well, but I suspect there are already several more capable disk emulators available for them. The Sorcerer had no built-in disk...

In model II (48K) Sorcerers, the cassette interface is on the motherboard, so the Teensy must connect directly to the UART: Remove the power supply daughterboard. Remove the UART IC from its socket at 9E. Slightly bend up pins 17, 20, 25, and 40, just enough to clear the socket when it's...

Wiring diagram for early (32K) Sorcerers: Remove cassette interface daughterboard and connect Teensy as shown:

Thanks! At 20833 baud with 2 stop bits, the transfer rate is 1.85K bytes/sec. I don't know what the typical rate was for CP/M machines but the Atari 810 was about 1.0 and the CBM 1541 about 0.5 KB/sec (they used serial ports). Apple Disk II was as high as 15 KB/sec!

Cool! What do the other 3 knobs do? What does the blue circuit board do?

I meant to say that CD WAV file loading is less than reliable. Teensy has proven quite reliable.

The Exidy Sorcerer (http://oldcomputers.net/sorcerer.html) is an early personal computer, arriving in 1978 on the heels of the Apple II, TRS-80, and PET. It features a 2 MHz Z80, up to 48K RAM, ROM cartridges (made from 8-track tape cases!), and a high-resolution monochrome display. Half the...

Failed to find that post again, but found this one which confirms that const is what matters on Teensy. https://forum.pjrc.com/threads/27445-Teensy-3-1-Serial-print(F(-quot-quot-))?p=61220&viewfull=1#post61220 Thanks, all, for your replies.

const is fine for named constants, but what about literal constants? Can't find the post now but thought Paul said they use RAM by default.

Thanks, that makes sense. Thought I read here recently that constants go into RAM too unless you F() them. Shame. Not the case with AVR?

Not a bug report probably, but I'm curious about Teensy RAM ("dynamic memory") usage in Teensyduino. When I compile the Blink example for the Arduino Mega 2560 under Arduino 1.8.8 and Teensyduino 1.45, I get this memory usage: Sketch uses 1472 bytes (0%) of program storage space. Maximum is...

Do some distributors choose not to include the pinout card?

Nice job on the emulators! Thank you for bring the wonderful Ataris to the amazing Teensy. Your demo videos could use some improvement, though, especially the sideways one. Perhaps some narration, a tripod, some editing (or a friend who can help with those)?

Amen, brother!

Wow, Frank B, I also learned 6502 (Atari 400) and Z80 (ZX81) assemblers, and worked on CDC Cyber, in college! Later, at work, I developed microcontroller systems with Z80, Intel 8048, 8041, 8051, and Motorola DSP56000. Great fun! I love the Teeny 3 series for its ease, size, power, and 5-volt...

over at Sparkfun. 3.5, 3.6, and some others are 20% off: https://www.sparkfun.com/categories/267

Yes, so many factors can affect performance. But it appears from kinetis.h that Paul has made some choices based on experience, or testing, or manufacturer specs. Apparently, F_MEM must be an integer divisor of F_CPU. Some of the overclocked settings show F_MEM as high as 32000000. So why not...

Well, I just discovered that there are links in that tech spec table! When I click on Bandwidth, I get: So the question now becomes: How does that value relate to F_MEM in kinetis.h ? There's a factor of 8 between the table value and F_MEM for T3.5 @ 120 MHz, so presumably there are 8 bytes...

In the tech specs https://www.pjrc.com/teensy/techspecs.html, what does Bandwidth mean, exactly? Is it just Bus Clock (words/sec) * 4 (bytes/word) ? If so, is the 192 MB/s value for T3.5 correct? From kinetis.h https://github.com/PaulStoffregen/cores/blob/master/teensy3/kinetis.h: #elif...

Thanks again. I selected the port you mentioned and it works. The other port was left over from the Arduino Nano I had plugged in before. Nice work on the Teensy BTW!

Maybe not so painless. I installed Teensyduino 1.16 over Arduino 1.0.5 on Mac OS X 10.6.8 and the Blink sketch works. I can modify it and download and run it but when I try the serial monitor I get this: Arduino: 1.0.5 (Mac OS X), Board: "Teensy 3.0" Binary sketch size: 18,400 bytes (of a...

Thanks. I found a tutorial for noobs like me which describes Paul's suggestion: http://rcarduino.blogspot.com/2012/09/how-to-view-arduino-assembly.html Someday I might try working outside the IDE. I love the painless ease of it. I'm a noob to Arduino and ARM, but not to microcontrollers. I used...

In Teensyduino, is there a way to view the assembly code produced by the compiler?

Thanks!!!!

I just tried it and it seems to work. I added __asm__("ldr r0,[r1]\n\t"); to the Blink example and it compiled. Is there documentation somewhere about which registers are OK to modify and how to get register values into C variables, etc.?

Hi. First-time poster here. Does Teensyduino C support the asm statement to embed ARM code for a Teensy3? If not, can C code be written to compile to a very tight loop, say ~5 cycles? Example loop: loop: read entire port C into reg compare reg with immediate value branch to loop if not...