HC08 monitor mode question

[voltaic]

This is probably a dumb question, but I have not found a definitive answer to it:

As I understand things, a bootloader, which must be programmed onto the chip beforehand is required to program the HC08 series while in user monitor mode, which is the monitor mode that does not require an external clock and the high voltage Vtst.

It is also my understanding that if you do have the external clock and Vtst, you can program the chips without a bootloader (ie if you had a completely blank chip)

is this correct?  

Also, does the QY series come with this bootloader programmed in from the factory?

Thanks!

[Lundin]

I'm a bit rusty at this, but if I remember correctly, "user monitor mode" is a bootloader software delivered with some evaluation boards, for quick & dirty evaluation. The normal chips are not delivered with this bootloader. To program blank chips you will indeed need a Vtst voltage, a clock, a reset and a mess of pull resistors on various pins.

I'd strongly advise to use the code-compatible HCS08 family if possible, to avoid the error-prone monitor mode entirely. HC08 is to be regarded as legacy anyway.

[voltaic]

I have heard this about the monitor mode being error-prone and unreliable, but haven't had the chance to play with it.  what is so error prone about it, and why?  

also, is there a cheap and easy way to build a programmer for the HCS series?  I have seen a few things about an "open"  programmer for them, but haven't really investigated.  anyone have any experience/thoughts on that?

[pgo]

Dear Voltaic,

You can check this discussion board  for Open-source BDMs for the HCS08/12.

OSBDM08: Open Source BDM for (R)S08 

bye

[Lundin]

The CPU needs all the pins to be in this or that state before starting up. If your real application for some reason puts a 5V or 0V on those pins while the CPU is starting, it will might lock up in the wrong mode. This is especially troublesome when using the SO8 versions of HC08 when you can't afford to let the monitor have dedicated pins. It messes up the design.

(Also, exposing the mcu reset pin to an external connector is always poor design no matter programming interface.)

There are "open" BDMs for HCS08/HCS12, those are mainly for hobbyist projects. For professional use, I can't see how I could possibly build my own BDM cheaper than the mass-produced commercial ones. Why waste time & money in re-inventing the wheel?