Going backwards, can't even get a basic blinky working now

[tumbleweed]

Regarding the overshoot issue, if your PICkit 4 is serial number BUR20xxxxxxx or later (-R2) then it has a mod in it to reduce the overshoot so it's not as much of a problem. Before that, they used to recommend using a 470R in series with the PK4 MCLR connection to the target.

From ETN37:

Some PIC16/18 devices have options to use high voltage on VPP or NMCLR to program the device. On some
devices, the VPP/NMCLR pin has special ESD protection. Overshoot on the pin can result in a reset condition or
current consumption outside of the specification. To avoid this situation, the data sheets for these devices
recommend the use of an RCR network with a pull-up, a power up charge capacitor and a series resistor
configuration into VPP. A series resistor of 470 ohms is used to dampen any overshoot and to limit current into
VPP/NMCLR

[Demon]

Regarding the overshoot issue, if your PICkit 4 is serial number BUR20xxxxxxx or later (-R2) then it has a mod in it to reduce the overshoot so it's not as much of a problem. Before that, they used to recommend using a 470R in series with the PK4 MCLR connection to the target.

From ETN37:

BUR223673449


Do you mean -R like a command line? Taken from the IPECMD docs:

R<on><off>

Safe/Restricted mode (Applicable only for MPLAB PM3)

Default = None

I'm running the PK4 from MCS+5.

Robert

[tumbleweed]

BUR223673449

Then it has the mod to address the ETN37 overshoot issue.

Do you mean -R like a command line?

No, I meant the PK4 assy number... usually on the label right above "BURxxx". On one of mine it's "10-10094-R2"

There's probably no real reason to put a zener on VDD. The overshoot was only on the VPP/MCLR high-voltage generator.

[Demon]

Then it has the mod to address the ETN37 overshoot issue.

No, I meant the PK4 assy number... usually on the label right above "BURxxx". On one of mine it's "10-10094-R2". ...

Mine is up to -R6.

... There's probably no real reason to put a zener on VDD. The overshoot was only on the VPP/MCLR high-voltage generator.

I wasn't really thinking of protecting VDD from the PK4. This was more to protect the circuit from being driven by who-knows-what wall-adapter by a user.

Robert

[Demon]

Talk about varying absolute maximum specs from one PIC to another:

16F877
Voltage on VDD with respect to VSS.................+7.5V
Voltage on MCLR with respect to VSS...............+14V

Was plan A, but I'm forgetting about the 16F877; keeping it for disposable pet projects now. I've wasted enough days trying to figure what I'm doing wrong.

18F4550
Voltage on VDD with respect to VSS.................+7.5V
Voltage on MCLR with respect to VSS...............+13.25V

Gotta be prepared to use this series, in case I ever get the C++ USB code figured out.

18F26K22
Voltage on VDD with respect to VSS.................+6.5V
Voltage on MCLR with respect to VSS...............+11V

This is my plan B unless there's something even sweeter out there, has 2 USART circuits. I could use one to talk to the PC via USB, and the other to talk with other PICs. Starting to test these as soon as my ZIFs come in. I'm making my own soldered test boards; not trusting the Lab-X1 with its funky blinking for no apparent reason.


I wish I knew absolute specs varied this much before; I never paid much attention to that. I've already put in a few order to DigiKey, Newark and Mouser for all sorts of odds and ends;including some Zeners.

Robert

"I'm killing the planet single-handedly with shipping."

[tumbleweed]

And then you've got the newer K and Q families...

18F26K40
Voltage on VDD with respect to VSS.................+6.5V
Voltage on MCLR with respect to VSS...............+9V

The 26K22 has been one of my "goto" devices for a long time.

[Demon]

Yeah, I got a bunch of 18F26K22 and 18F46K22 from MicroChipDirect a while ago, as well as a bunch of other ICs (sensors, i/O interfaces, etc).

Has MicroChip come up with a newer better USB series than the 18F2550/18F4550?


EDIT: Yeah, this is an interesting MCU: PIC18F04/05/14/15Q40.

I need to find a smaller package though, something with 3-4 I/O pins that can USART at a good clip. These look interesting (not really interested in the low-voltage line):

16F18015/25/44/45
16F18313/18323

(...runs off to MicroChip Direct to see if they still offer 3-demos to customers...)

Robert