TMS320F243FN datasheet(27/116 Pages) TI

27 / 116 page

TMS320F243, TMS320F241

DSP CONTROLLERS

SPRS064B – DECEMBER 1997 – REVISED FEBRUARY 1999

POST OFFICE BOX 1443

• HOUSTON, TEXAS 77251–1443

reset

The reset operation ensures an orderly startup sequence for the device. There are two possible causes of a

reset, as shown in Figure 5.

Signal

Reset

System Reset

Watchdog Timer Reset

External Reset (RS) Pin Active

Figure 5. Reset Signals

The two possible reset signals are generated as follows:

D Watchdog timer reset. A watchdog-timer-generated reset occurs if the watchdog timer overflows or an

improper value is written to either the watchdog key register or the watchdog control register. (Note that

when the device is powered on, the watchdog timer is automatically active.) The watchdog timer reset is

reflected on the external RS pin also.

D Reset pin active. To generate an external reset pulse on the RS pin, a low-level pulse duration of at least

one CPUCLK cycle is necessary to ensure that the device recognizes the reset signal.

Once watchdog reset is activated, the external RS pin is driven (active) low for a minimum of eight CPUCLK

cycles. This allows the TMS320x24x device to reset external system components.

The occurrence of a reset condition causes the TMS320x24x to terminate program execution and affects

various registers and status bits. During a reset, RAM contents remain unchanged, and all control bits that are

affected by a reset are initialized to their reset state.

hardware-generated interrupts

The ’24x CPU supports one nonmaskable interrupt (NMI) and six maskable prioritized interrupt requests. The

’24x devices have many peripherals, and each peripheral is capable of generating one or more interrupts in

response to many events. The ’24x CPU does not have sufficient interrupt requests to handle all these

peripheral interrupt requests; therefore, a centralized interrupt controller is provided to arbitrate the interrupt

requests from all the different sources. Throughout this section, refer to Figure 6 .

TMS320F243FN Datasheet(PDF) 27 Page - Texas Instruments