Russ, to be sure, contact Microchip. I took another look at the PIC16C7X
data book (DS30390E, page 141) and it only mentions 16C73/74 devices. When
I moved to 16C76/77 devices, I retained the GIE test bit loop.

   - Tom

At 01:34 PM 6/18/98 -0400, Russ Steinbach wrote:
>I have a question on clearing the Global Interrupt Enable (GIE) bit on the
>16C77 chips.
>
>On the older 16C74 chips, when you cleared the GIE you had to loop until you
>were certain that the bit was cleared.  This was due to a problem where if
>an interrupt occurred as you were clearing the GIE, your ISR would execute
>and re-enable the GIE on completion of the ISR.
>
>The new manual implies that this bug may have been fixed on the '77 chip.
>However we are experiencing a problem (very low occurrence rate and
>difficult to pin down) that *could* be explained by this known bug on the
>older '74 chip.
>
>So my question is: Did they fix this problem, or do they need to fix the new
>data sheet?
>
>Any help will be appreciated!
>
>Russ Steinbach
>Russ Steinbach
>Manager, Research and Analysis Dept.
>Analex Corporation
>3001 Aerospace Parkway
>Cleveland, OH  44142
>
>(216) 977-0094 (W)
>(216) 977-0200 (F)
>Steinbach@lerc.nasa.gov
>
>