Questions About BDM & 9s08GT16

[Wings]

The BDM port coming from a Cyclone Pro has a connection for Vcc.

Is this one of its methods for powering up/down your GT16 target?

Does a 9s08GT16 need to be power cycled in order to reprogram it?

Can I leave off the BDM Vcc connection to my target?

Previously I've used the Vcc from the BDM on the Cyclone to power a QG8 target and that seemed to work just dandy. But I'm running under the assumption that a 9s08GT16 doesn't need a power cycle for reprogramming. Don't know where I picked up that info.

I'm laying out my GT16 board now, so please, if you answer, be accurate. I'm going to go by the answers I get here.

[Encoder]

My USB Multilink from P&E has no power on BDM. It needs to be powered on the BDM interface from the target power: so the target NEEDS to be self powered in order to be programmed or simply to communicate to BDM. And the pod is powered by the USB cable.

The logic part of the Multilink is obviously powered from the USB connection: I think that the reason why the BDM port is not powered from the programmer is in order to be interfaced with 3V or 5V mcu. In fact I use 9S08AW60 which has 5V supply.

On the contrary to HC908, 9S08 do not need to be power cycled to communicate with BDM, so I think that, if Cyclone Pro has internal connection of power supply to BDM, it must be for convenience to possibly use it to alternatively power up the target board. Or to be powered from it.

In the former case it should have provision to either commutate to 3 or 5V or to remove the connection.

From the 9S08GT/GB data sheet it is stated that the Vdd connection to the BDM port on the target can be used to power pods which do not have their own power supply, like those connected to pc through serial cables. Anyway the standard assume that your target BDM port has its connection to Vdd supply of the processor, so you would need to design it.

Message Edited by Encoder on 2006-12-1511:22 PM

[peg]

Hi Wings,

Not sure why you want to do this.

A P&E USBBDM needs the connection there as the target power powers the interface circuitry and there is no option to power up the target from the pod.

Don't know if the Cyclone needs this if you don't use it to power target.

Certainly using this method (I did it yesterday on a GT16) You can plug in the USBBDM into a running target, then without touching the power, stop it erase it reprogramme it secure it and restart it.

Regards

Peg