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Hi
I'm encountering strange behaviour when programming a 16F874 in circuit.
I have used a Schottky diode to isolate the programming voltage from the =
supply voltage while
programming as recommended in the Microchip technical brief on ICSP.
If I try to modify some code, then the PIC will boot when I try to =
program it.
Has anybody else noticed this behaviour?
Is it down to the selection of the diode?
I've checked the voltages on the MCLR/Vpp pin when in normal operation =
and while programming and
I see 5V in normal operation and 13V when programming.
The attached sketch shows what has been done.
Any hints?
Alan
Embedded Systems Engineer
Microtima Ltd
Ouseburn Mews
3-7 Stepney Bank
Newcastle upon Tyne
NE1 2PW
Tel: 0191 2304411
Fax: 0191 2304422
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Hi
I'm encountering strange behaviour when programming =
a 16F874=20
in circuit.
I have used a Schottky diode to isolate the =
programming=20
voltage from the supply voltage while
programming as recommended in the Microchip =
technical brief on=20
ICSP.
If I try to modify some code, then the PIC will boot =
when I=20
try to program it.
Has anybody else noticed this =
behaviour?
Is it down to the selection of the =
diode?
I've checked the voltages on the MCLR/Vpp pin when =
in normal=20
operation and while programming and
I see 5V in normal operation and 13V when=20
programming.
The attached sketch shows what has been =
done.
Any hints?
Alan
Embedded Systems =
Engineer
Microtima=20
Ltd
Ouseburn Mews
3-7 Stepney Bank
Newcastle upon Tyne
NE1=20
2PW
Tel: 0191 2304411
Fax: 0191=20
2304422
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