ISP entry with 89lpc932

[Roland]

Hello to all,
i have read the AppNote 3, but i have still some questions relating
to the MCB900 Schematic and how FlashMagic works with it...

1) Can someone please explain the cooperation between Flash Magic
and the MCB900 Schematic in more detail?

It looks to me, that a character has to be send to pulse the RESET pin... ?
The functionality is well explained for the /PSEN & RTS method,
but not for the P89lpc932 RESET & VDD method.

2) Is the 74HCT NOR Device powered by 5 Volts or by 3 Volts?
The specs tell me that is is an 5 Volt device.

3) Why are the DTR and RTS Signals applied directly (via some resistors)
to the 74HCT02 and not passed through the RS232 converter?

4) The Flash Magic Manual tells me, that custom hardware will be
supported at a later date. Is it still true or is the Keil Schematic
the only supported method ?

Sorry for that many questions.  Please help me ...

Roland

[Andy Ayre]

Roland wrote:

> Hello to all,
> i have read the AppNote 3, but i have still some questions
> relating
> to the MCB900 Schematic and how FlashMagic works with it...
>
> 1) Can someone please explain the cooperation between Flash
> Magic
> and the MCB900 Schematic in more detail?

It is planned to add this to application note 1 at some point in the very near future.

> It looks to me, that a character has to be send to pulse the
> RESET pin... ?
> The functionality is well explained for the /PSEN & RTS method,
> but not for the P89lpc932 RESET & VDD method.

What happens is an inverted character is sent to the RESET pin. DTR and RTS control both the power supply to the device and whether Rxd is inverted and connected to RESET. The inverted character appears as the pulses needed.
 
> 2) Is the 74HCT NOR Device powered by 5 Volts or by 3 Volts?
> The specs tell me that is is an 5 Volt device.

Not sure about this.
 
> 3) Why are the DTR and RTS Signals applied directly (via some
> resistors)
> to the 74HCT02 and not passed through the RS232 converter?

The RTS needs to be inverted, and the RS232 voltage level is already inverted with respect to the TTL voltage levels. The DTR is not passed through the RS232 converter because originally RTS was, and there were no tranceivers left on the RS232 converter.
 
> 4) The Flash Magic Manual tells me, that custom hardware will
> be
> supported at a later date. Is it still true or is the Keil
> Schematic
> the only supported method ?

It is still true, but currently the Keil design is the only one supported. If we were to design our own hardware it would be very similar but remove the need for the jumpers.
 
> Sorry for that many questions.  Please help me ...
>
> Roland
>
>

[Roland]

Hello Andy,
thank you for the additional hints.

The Keil shematic needs some clean up, anyway...
The RTS Signal is connected to the RS232 receiver
and its equivalent output pin is not used. Ok, that's
not important.

I will make my own design when you add an application
note as promised in the near future..

Thank you for your help.

Roland