80C187 datasheet(20/30 Pages) INTEL

20 / 30 page

80C187

System Configuration for 80186

80187-Compatible Exception Trapping

When the 80C187 ERROR output signal is connect-

ed directly to the 80C186 ERROR input floating-

point exceptions cause interrupt

16 However ex-

isting software may be programmed to expect float-

ing-point exceptions to be signalled over an external

interrupt pin via an interrupt controller

For exception handling compatible with the 80186

821888087 the 80C186 can be wired to recognize

exceptions through an external interrupt pin as Fig-

ure 10 shows (Refer to the 80C186 Data Sheet for

an explanation of the 80C186’s signals) With this

arrangement a flip-flop is needed to latch BUSY

upon assertion of ERROR The latch can then be

cleared during the exception-handler routine by forc-

ing a PCS pin active The latch must also be cleared

at RESET in order for the 80C186 to work with the

80C187

270640 – 8

For input clocking options refer to Figure 9

Figure 10 System Configuration for 8087-Compatible Exception Trapping

80C187 Datasheet(PDF) 20 Page - Intel Corporation