Breadboard-friendly Propeller module?
David Betz
Posts: 14,511
Does anyone know of a breadboard-friendly Propeller module that has an onboard USBserial connection? I know about the PropStick USB but $49 is a bit more than I want to pay. I have a Prop-Mini but it can't be powered over USB.
Comments
I've also seen the need for a decoupling capacitor on the power into the ESP module. On the Espruino shield for the ESP-01, for example, a 47uF capacitor is recommended. Other applications go with anything from 10uF on up. I just read that the ESP can have a burst current draw of 300ma during some operations. Without the capacitor, the modules can act flaky; busy status, lost connections, etc.
Larger electrolytic capacitors are needed for circuits that intermittently draw heavy currents for time periods in the millisecond range. They act as a current reservoir, but the high ESR of those capacitors cannot respond to the microsecond or shorter current pulses high speed logic circuits produce. For those circuits lower value low ESR tantalum, ceramic, and film capacitors are needed.
Note that under the "Power" heading they state "A feature of this device is that the second 3.3V regulated power also has a 1000uF capacitor to act as a 'reservoir'."
If you use the P8XBlade2 winging its way to you, together with the USB-Serial CP2102 I linked to (~US$1.50 on eBay), that will make a breadboard friendly connection that is USB powered.
Provided the PC/Laptop can supply enough power for the ESP8266 - Don't connect anything larger than say 47uF tantalum because the USB spec actually says 10uF IIRC. Hopefully this will provide enough bulk power to avoid the brownout problem on the ESP8266.
You can directly connect the USB/serial to my board but you will have to
(1) ensure the 3v3 output pin from the USB/Serial makes no contact
(2) bend the DTR pin (or wire) 0.1" sideways to the next 0.1" grid (I just couldn't put the reset pin in the correct position on the pcb no matter how hard I tried
Get the ESP8266 download working by using a spin/pasm program working under PropOs (or spinix) that simulates the reboot and download without the reset, and waits for the download protocol. That is how I was going to attempt to be able to download without the download timing restrictions. It would be easiest to get this working using the USB/serial first. Did I explain this sufficiently??? use the P1 bootcode rom source as the basis.
Very nice board indeed.
https://www.parallax.com/product/32210
I have thought that to run a "special boot program" on the prop that is almost the same as the rom boot code, but waits indefinitely for the startup sequence, and when found completes the handshake and loads into hub ram and optionally programs the eeprom, and then runs that code.
Of course there are other ways such as getting the ESP8266 code to use a GPIO as a reset line to the prop.
As for the 3V3 required for the ESP8266, the regulator I use on my modules will not power the ESP8266 properly due to the high power spikes required by the ESP8266 module. There is plenty of power for other things, but ~300mA surge doesn't have enough pcb area for power dissipation even with only 5V header.
Nice circuit construction, do you know the boards material? Couldn't find it at adafruit.
I read it again, but is the board glass epoxy?
Next I'm going to work on a two-stage loader so the second stage can run at a really high speed.
So that the left side would have headers for P0 to P31. Then, it would have another 8 pin header for the misc pins.
The right side would be the same only mirrored for the second propeller.
The two propellers would not be connected (you would have to jumper them).
But the board would be very thin (but long). The two sides would be separated by the middle section of the breadboard.
Then, maybe two prop-plug headers on the top/bottom for each propeller.
Seems like it would be a simple board to design. If I could only make my lazy self do it.
It reminds me Basic Stamp Modules - BS1 and BS2.