I have now ordered a series of parts from Mouser. This includes some lead free solder (ouch that stuff is expensive), flux, several different crystal oscillators and what I THINK to be matching capacitors, as well as a ton of headers for jumper cables. I entered a ticket for Microchip more than a week ago and have received no response whatsoever from them regarding the oscillator. Reading the instructions there was no mention of a type of crystal to use beyond 32khz. They mentioned 11pF capacitors of 0603 size. From what I can understand it SOUNDS LIKE in a properly designed board if you have a 6 or 7pF crystal you install an 11 to 14pF capacitor when it has short runs for the wiring etc. HOWEVER yesterday I found on the ethernet board they explicitly defined the crystal as a 12.5pF crystal. In my observations it appears that if you use 12.5pF crystals you should use 22-27pF capacitors, though.<\/p>\n
The unfortunate problem is some people report using 11\/12 capacitors with 12pF crystals and other report needing to use 27 etc. I’m thinking it MAY depend on the manufacturer of the crystal as to how sensitive it is and needing more or less power from the caps to be held up to trigger the oscillations of the crystals in addition to the variables of the individuals circuit layout. In other words some times it works no matter what and others it does not.<\/p>\n
I still need to get some solder paste in addition to the rolled wire solder. I had issues identifying this on the Mouser website in the search except for a couple versions that had more than five tubes as a minimum. I do not have need for \/ ability to consume more than one syringe\/tube right now so I need to find a vendor to procure some from that does one at a time. I stumbled across one a few nights ago that sells one at a time but I’ve not had time to dig through the browser history to find my way back there yet.<\/p>\n
Once I have the solder paste and after the parts arrive mid week I can solder in the crystal and caps to see if they work for the timing functions and continue my efforts at programming the interface. Most of my programming is going to wrap around being able to gauge time changes happening so I need to wait for that to happen.<\/p>\n
Currently I have a thermocouple breakout board that I will be attaching to some of the IO lines. I also have on order a relay board that has not arrived. Once the relay board arrives I can attach it to the development board and configure it to turn on the fan when the program run starts and not to turn it off until after the heat drops to a safe level. The heat will trigger on and off to maintain the desired ramp at this time. I will eventually replace it with a variable “dimmer” once I work out the other kinks in the system to give it finer control. <\/p>\n","protected":false},"excerpt":{"rendered":"
I have now ordered a series of parts from Mouser. This includes some lead free solder (ouch that stuff is expensive), flux, several different crystal oscillators and what I THINK to be matching capacitors, as well as a ton of headers for jumper cables. I entered a ticket for Microchip more than a week ago and have received no response whatsoever from them regarding the oscillator. Reading the instructions there was no mention of a type of crystal to use beyond 32khz. They mentioned 11pF capacitors of 0603 size. From what I can understand it SOUNDS LIKE in a properly \u2026 Continue reading