Equinox Systems GEMINI Podręcznik Użytkownika Pobierz pdf (Strona 43)

User Guide V1.10

Notes

P89C51Rx+ family

These devices require a Vpp of +12V to be applied to the ‘EA/Vpp’ pin of the target

microcontroller. The Vpp is generated on-board the Gemini programmer and is output on

the ‘PROG_VPP’ pin during a programming operation. The ‘PROG_VPP’ pin outputs +5V

(i.e. Vcc) at all other times.

Circuit instructions/notes:

• Connect the ‘PROG_VPP’ pin the ‘EA\Vpp’ pin by fitting J1

• Fit components R2, C5 and D2

• Try to fit C5 as close as possible to the ‘EA/Vpp’ pin of the target microcontroller on the

target system.

• Do NOT fit J2

• Make sure that the target power supply can cope with a large inrush current for a short

period of time as the Gemini ‘Vpp Generator Circuit’ powers up.

These devices requires a +12V Vpp signal to be applied to the ‘EA/Vpp’ pin of the target

microcontroller. The microcontroller draws the ‘programming current’ through this pin, so

it is imperative that the Vpp pin is suitable decoupled to avoid any glitches.

P89C51Rx2 family

These devices require a Vpp of only +5V (i.e. Vcc) to be applied to the ‘EA/Vpp’ pin of the

target microcontroller. If a Philips P89C51Rx2 device is selected from the Gemini software,

he ‘PROG_VPP’ pin will always be kept at +5V (i.e. Vcc).

Warning!

If a P89C51Rx+ device is selected by mistake, the programmer will apply +12V Vpp to the

‘EA\Vpp’ pin. This may cause catastrophic damage to both the target system and the

programmer. It is therefore recommended that the ‘PROG_VPP’ pin is simply connected to

the target system when using P89C51Rx2 devices.

Circuit Notes

• Disconnect the ‘PROG_VPP’ pin by removing J1

• Do NOT fit components R2, C5, D2 (only required for Vpp of +12V)

• Connect the EA/Vpp pin to Vcc by fitting J2

These devices require only a +5V (i.e. Vcc) Vpp to be applied to the ‘EA/Vpp’ pin of the

target microcontroller. The microcontroller draws the ‘programming current’ through the

Vcc pin, so it is imperative that the Vcc pin is suitable decoupled to avoid any glitches.

ISP Target System Design Guide - Philips Microcontrollers

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Equinox Systems GEMINI Podręcznik Użytkownika Strona 43