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TI486 Microprocessor - Al Kossow's Bitsavers

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Functional Timing<br />

Shutdown Indication Cycle<br />

Figure 3-15. Pipelined Shutdown Cycle<br />

Shutdown occurs when a severe error is detected that prevents further<br />

processing. The <strong>TI486</strong>SLC/E microprocessor shuts down as a result of a<br />

protection fault while attempting to process a double fault as well as the<br />

conditions referenced in Chapter 2. Signaling its entrance into the shutdown<br />

state, a shutdown indication cycle is performed. The shutdown indication cycle<br />

is identified by the state of the bus cycle definition signals (M/IO=1, D/C=O,<br />

W/R=1, LOCK=1) and an address of Oh (A23-A 1 =0, BHE=1, BLE=O). The<br />

shutdown indication cycle must be acknowledged by READY asserted. A<br />

shutdown <strong>TI486</strong>SLC/E microprocessor resumes execution only when NMI or<br />

RESET is asserted. Figure 3-15 illustrates a shutdown cycle using pipelined<br />

addressing.<br />

ClK2<br />

1 Cycle 1 1<br />

1 Pipelined 1<br />

1 (Read) 1<br />

1II1II<br />

.1II1II<br />

1 1<br />

1 T1P T2P 1<br />

1 1<br />

Cycle 2 1<br />

Pipelined 1<br />

(Shutdown) 1<br />

~<br />

1<br />

T1P T2P 1<br />

1<br />

Idle<br />

Ti Ti Ti<br />

II~I.II<br />

CPU remains shut-<br />

1<br />

MIlO, BHE W/R Valid 1 /<br />

I down until NMI, or<br />

---'---""'1 BlE is low for 1 RESET is ?Sserted. :<br />

:<br />

ShutdovynCycle<br />

A23-A 1, Valid 1 \ 1<br />

BlE, DIG<br />

: :<br />

~II<br />

---,-----~------~I------~~~~~~~~~~~~~~~~~~~<br />

1 I I : I I I I I<br />

ADS --.1...1 ---Ir.il~ Villi 1 :<br />

READY<br />

1 1 1 1 1 1 I<br />

I I<br />

NA~~~<br />

i~i~i---<br />

1 I I<br />

1 Note: Shutdown cycle must be acknowledged by READY<br />

1 asserted. Wait staes may be added to the cycle if desired.<br />

I I i I I 1 1<br />

LOCK; vali~1 7 i ~<br />

1 1 1 1 1 1 1 1<br />

D1~DO --+--~-

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