On 11/14/22 10:11, Brian K. White wrote:
On 11/14/22 09:12, Brian White wrote:
The datasheet says to rest vpp at vcc. Most do, even if elsewhere they
also say that writing is disabled as long as vpp is below vpp and the
only low limit is pretty much the same as for any other pin, like 0.5
or 0.7 below vcc.
derp I mean the low limit is a little below GND or VSS not VCC.
Although a Microchip 27C64 datasheet I happen to be looking at at the
moment does actually say the vpp read voltage is min vcc-0.7, max vcc.
More derp, I obviously confused VPP with /WE there.
But pin 27, being /WE (/PGM), still needs to be held at VCC not GND,
although theoretically any writes should still fail without VPP, but
still, you just hold /WE at VCC for reads.
--
bkw
