Control of Single Flip-flops
The control gates for the seven flip-flops can be determined in a similar manner. For example, Table 5-6 shows that lEN may change as a result of the two instructions ION and !OF.
pB7: lEN +-1
pB6: lEN +-0
where p = D71T3 and B, and B, are bits 7 and 6 of lR, respectively. Moreover, at the end of the interrupt cycle lEN is cleared to 0.
RT2: lEN +-0