Immediately following any type of system reset
(power-up reset, PWRGOOD reset, watchdog timer timeout, lamp-strike reset), the DLPC6422 device automatically returns to NORMAL power
mode in the following state:
- All GPIOs are tristated.
- The primary PLL remains active (it is reset only after a
power-up reset sequence), and most of the derived clocks are active.
However, only those resets associated with the ARM9 processor and its
peripherals are released (the ARM9 is responsible for releasing all other
resets).
- ARM9-associated clocks default to the full clock rate.
(Boot-up is at full speed.)
- All front-end clocks derived are disabled.
- The PLL feeding the LVDS DMD I/F (PLLD) defaults to its
power-down mode, and all derived clocks are inactive with corresponding
resets asserted. (The ARM9 is responsible for enabling these clocks and
releasing associated resets.)
- LVDS I/O defaults to its power-down mode with outputs
tristated.
- All resets output by the DLPC6422 device remain asserted until released by the ARM9(after
boot-up).
- The ARM9 processor boots up from external flash.
When the ARM9 boots-up, the ARM9 API:
- Configures the programmable DDR Clock Generator (DCG) clock rates (that is, the
DMD LVDS I/F rate)
- Enables the DCG PLL (PLLD) while holding divider logic in reset
- When the DCG PLL locks, the ARM9 software sets the DMD clock rates.
- API software then releases DCG divider logic resets, which in turn, enable all derived DCG clocks
- Release external resets
Application software then typically waits for a wake-up command (through the soft power switch on the projector) from the end-user. When the projector is requested to wake up, the software places the ASIC back in normal mode, reinitializes clocks, and resets as required.