Intel 386 - Manual (Page 193)

Intel386™ EX EMBEDDED MICROPROCESSOR USER’S MANUAL
8-12
Figure 8-8. Reset Synchronization Circuit
8.4.2 Power-up Considerations
8.4.2.1 Built-in Self Test
The Intel386 EX processor supports the Intel386 SX processor built-in self-test (BIST) mode for
testing core functions. To initiate the self test, follow these steps:
1. Hold the RESET pin high for a minimum of 80 CLK2 cycles.
2. Transition the RESET pin from high to low while keeping the BUSY# pin asserted. The
BUSY# input should be asserted at least eight CLK2 cycles before the falling edge of
RESET and must be kept asserted for at least eight CLK2 cycles after the falling edge of
RESET.
Once BIST has been initiated, it takes approximately 2
20
processor clock cycles to complete. At
the completion of the BIST, the processor performs an internal reset and begins normal operation.
8.4.2.2 JTAG Reset
The processor supports an IEEE 1149.1 compliant JTAG boundary scan. The JTAG unit has its
own clock and RESET signals, independent from the rest of the processor. The processor requires
that the JTAG unit be reset before normal operation can begin. To reset the JTAG unit, invert the
processor RESET signal and connect this inverted RESET signal to the TRST# pin.
Synchronous
Reset Signal
to chip and
other system
logic.
D Q
CLK2
Asynchronous RESET D Q
A2465-02