PIC16F1789 won't program at 3.3V, but programs at 5V

webgiorgio · Joined: 02 Oct 2009 Posts: 123 Location: Denmark

Hi,
I have a PIC16F1789 that I want to operate at 3.3V (as there will be other 3.3V devices in the circuit).
I can program it at 5V (Vcc), and then it will run at 3.3V (Vcc) (simple blinking LED).
The problem is that the chip won't program at 3.3V. I get "Download Failed", diagnostics can't read the chip id. Vdd is 3.3V.

I am using a ICD-U64 programmer. For the tests I am powering the target from the programmer (selecting the jumper for 5V or 3.3V).
I understood that I am using the "high voltage programming" method.
I use

#fuses NOLVP
#use delay(clock=8M)

webgiorgio · Joined: 02 Oct 2009 Posts: 123 Location: Denmark

How can I disable "block erase"?

I read that the chip can be programmed at 3.3V using a "normal erase" of the memory rather than "block erase".

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

In the CCSload program, on the right you will see Options.
Click on the little double arrow, and it will give you more options.
It will show the Erase Mode options, which are:

- Bulk erase chip before programming
- Erase only blocks in hex file

Pick the one you want.

You can click on "make these settings be the default" on the
right side of the window.