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@ -2290,6 +2290,72 @@ place holder |
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placeholder |
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Diagnostics |
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-------- |
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### DIAG |
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Progress through the boot and initialization process can be difficult to monitor |
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due to the lack of console or video output. Access to these output devices does |
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not become available until late the in the boot process. If these output devices |
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are also involved with the issue trying to be resolved then trouble shooting is |
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even more difficult. |
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ROMWBW can be configured to display boot progress with the assistance of additional |
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hardware. This take the form of an LED breakout debugging board connected to an |
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8-bit output port. As the boot code executes, the LED output display is updated. |
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To us an LED breakout board, it must be connected the computers data, reset and port |
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select lines. |
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To enable the DIAG option the following settings must be made in the systems .ini |
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configuration file, where 0xnn is the port address. |
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DIAGENABLE .SET TRUE |
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DIAGPORT .SET 0xnn |
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The following table shows the ROMWBW process steps in relation to the LED display. |
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| LED | ROMWBW Processes | |
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| -------- |:---------------------------------------------- | |
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| `........` | Initial boot | |
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| | Jump to start address | |
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| | Disable interrupts | |
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| | Set interrupt mode 1 | |
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| | Initialize critical ports and initial speed | |
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| `.......O` | Setup initial stack | |
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| | Memory manager and CPU configuration | |
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| | Set top bank to be RAM | |
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| `......OO` | Get and save battery condition | |
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| | Install HBIOS proxy in upper memory | |
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| | If platform is MBC reconfigure memory manager | |
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| | Setup "ROMLESS" HBIOS image or ... | |
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| | Copy HBIOS from ROM to RAM if RAM flag not set | |
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| | Jump to HBIOS in RAM | |
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| | Set running in RAM flag | |
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| `.....OOO` | Finalize configuration for running in RAM | |
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| | Check battery condition | |
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| | Check for recovery mode boot | |
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| `....OOOO` | Identify CPU type | |
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| `...OOOOO` | Set cpu oscillator speed | |
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| | Setup counter-timers | |
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| | Setup heap | |
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| `..OOOOOO` | Preconsole initialization | |
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| `.OOOOOOO` | Boot delay | |
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| | Set boot console device | |
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| | Bios announcement | |
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| `OOOOOOOO` | Display platform information | |
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| | Display memory configuration | |
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| | Display CPU family | |
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| | Verify ROM checksum | |
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| | Report battery condition | |
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| | Perform device driver initialization | |
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| | Report watchdog status | |
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| | Mark HBIOS heap so it is preserved | |
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| | Switch from boot console to CRT if active | |
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| | Display device summary | |
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| | Execute boot loader | |
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`\clearpage`{=latex} |
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b1ackmai1er
3 years ago