ST72F321 VPP Pin conditions in normal mode

[u2]

Posted on January 14, 2004 at 13:45

ST72F321 VPP Pin conditions in normal mode

[u2]

Posted on January 14, 2004 at 13:09

dear support team,

we use in our automotiv application the ST662A charge pump to generate the Vpp programming voltage to progarmm the ST72F321. When charge pump is in shutdown mode the output voltage Vout = Vcc. This means that in normal operation mode Vcc is conected to Vpp.

I found a answer in subject 'Vpp' that the chip will work fine if Vpp has low level. What does 'low level' means and will Vcc satisfy the start conditions for the Vpp logic? - or - with other words, will the ST72F321 works without problems if Vcc is connected to VPP?

Thanks in advance

regards Uwe

[sjo]

Posted on January 14, 2004 at 13:45

You need to disconnect the Vcc from Vpp during normal operation, eg. using a mosfet. Have a look at page 30 of the Flash programming manual for an example

http://www.stmcu.com/mcdfiles/1072800075.pdf

Regards

sjo