On 7/16/07, Michael Rigby-Jones <Michael.Rigby-Jones@bookham.com> wrote:
> we spoke to Microchip technical support who insisted that the
> Promate 3 was incapable of programming at 3.3v, and that we
> should have read the specs before buying it etc.
>
> So, is the Mchip rep talking through his backside (as I strongly suspect),
> or is Microchips flagship production programmer really incapable of
> programming at 3.3v? (I'm aware of the issues of bulk erase not being
> possible at low voltage, none of the code is protected for this reason).
>

He might well be correct. Many programmer will issue a bulk erase
first even when the code protect is not on.

So you need to design the circuit to be ready for ICSP. Olin has
some good advice here.
http://www.embedinc.com/picprg/icsp.htm

I am not so sure how Promate III works since I do not have
access to an Promate III after I switched job last June.

However, it seems to me that PICKit 2 V2.40 can program
the chip at 3.3V **at certain condition**. Please refer to the
readme enclosed. Promate III and ICD2 may be able to do
so with the right firmware/host software. This is made possible
by using the alternative slower row erase method for many
PICs including all PIC18F device. I know ICD 2 is capable of
this before PICKit 2 V2.4.

Regards,
Xiaofan

PS: From PICKit 2 V2.4 Readme

> Low Vdd programming of selected Midrange parts, all PIC18F, and
  most dsPIC30F parts.
   -----------------------------------------------------
  |NOTE: Low Vdd programming WILL NOT WORK if any       |
  |config code, data, or write protect bits are active! |
   -----------------------------------------------------
   -----------------------------------------------------
  |NOTE: This is not the same as LVP programming, which |
  |uses the PGM pin for program mode entry.             |
   -----------------------------------------------------
  Previously, programming always used a Bulk Erase which required
  a minimum Vdd of 4.5V for Midrange parts, many PIC18F parts,
  and dsPIC30F parts.
     Midrange: Some Midrange parts support a flash row erase
               process at below 4.5V.  These devices are now
               supported for programming at Vdd < 4.5V using
               the row erase.
               See the device support list for supported parts.

     PIC18F:   All PIC18F parts now program down to 3.0V.  Some
               will program at lower voltages; the user will be
               warned if the voltage is too low.

     dsPIC30F: Most dSPIC10F devices now program down to 3.0V.
               The exceptions are the dsPIC30F5011 and
               dsPIC30F5013.

   -----------------------------------------------------
  |NOTE: The [ERASE] button/menu still uses Bulk Erase  |
  |only.                                                |
   -----------------------------------------------------
  Therefore, [ERASE] cannot be used at voltages below the Bulk
  Erase minimum Vdd.
  Parts that support the low Vdd programming can be left erased
  by following these steps:
  1) Connect to the device
  2) Select menu Device Family -> {family of device in use}
        This clears all buffers to the erased state
  3) Click [WRITE]
  4) The device is now in a completely erased state.
     (NOTE this will not work if any protect bits are set)
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