User manual

10.3 Types of Reset
10.3.1 Power-On Reset (POR)
10.3.2 Warm Reset
www.ti.com Types of Reset
Power-on reset (POR) is initiated by the POR pin and is used to reset the entire chip, including the test
and emulation logic. Power-on reset is also referred to as a cold reset, since the device usually goes
through a power-up cycle. During power-up, the POR pin must be asserted (driven low) until the power
supplies have reached their normal operating conditions.
The following steps describe the POR sequence:
1. Apply power and clocks to the chip and drive POR low to initiate POR.
2. Wait for the power supplies to reach normal operating conditions while keeping the POR pin asserted
(driven low).
3. Wait for the input clock source to be stable while keeping the POR pin asserted (driven low).
4. Once the power supplies and the input clock source are stable, the POR pin must remain asserted
(low) for a minimum number of DEV_MXI cycles (see device-specific data manual for number of
cycles).
5. Hardware latches the device configuration pins on the rising edge of POR. The device configuration
pins allow you to set several options at reset. See Section 10.4.1 for more information.
6. Hardware resets all of the modules, including memories and emulation circuitry.
7. POR finishes, all of the modules are now in their default configurations, and hardware begins the boot
process.
See the device-specific data manual for power sequencing and reset timing requirements.
A Warm reset is activated by driving the RESET pin active-low. This resets everything in the device,
except the test or emulation logic. A DSP or ARM emulator session will stay alive during warm reset.
The following steps describe the Warm reset sequence:
1. Emulator drives RESET low to initiate Warm reset.
2. Emulator drives RESET high after a required minimum number of MXI clock cycles.
3. Hardware latches the device configuration pins on the rising edge of RESET. The device configuration
pins allow you to set several options at reset. See Section 10.4.1 for more information.
4. Hardware resets all of the modules including memories, but not the emulation circuitry.
5. Warm reset finishes, all of the modules except emulation logic are in their default configurations, and
hardware begins the boot process.
See the device-specific data manual for reset timing requirements.
SPRUEP9A – May 2008 Reset 113
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