Motorola PPC/PMC-8260/DS1, Reference Manual, Page: 78 / 150

Loading Application Software Firmware
4 - 14 PPC/PMC-8260/DS1
Monitoring Boot Process
When PCR[INI] is set, the firmware sets status information in the mailbox
register 6 of the PowerSpan II PCI-to-60x bus bridge (offset 468
16
) where it can be
read by software. In this context, this register is referred to as power-up status reg-
ister (PSR).
Before resetting the board, the host should set this register to its reset value of zero.
After the module has been started, host software must poll the PSR for a non-zero
value before accessing local resources on the 60x bus. Otherwise, the PMC module
would hang because a non-zero value means the power-up procedure is not com-
pleted. The following values and their mnemonics are defined:
• 1 (POST)
This value is set immediately before the power-on self-test is started.
• 2 (RDY)
This value is set after all initialization steps and optionally the POST are com-
pleted and the primary booter is about to be executed.
• 3 (ROMEX)
This value is set after all initialization steps and optionally the POST are com-
pleted and a ROM image has been detected and is about to be executed.