This chapter is a
draft.
See the outline.
Startup and booting
The startup sequence and boot process of the Atari Lynx involves many steps and code from the cartridge and Mikey ROM.
Word count: 331
In this chapter:
Mikey boot process
Mikey can have its memory range of $FE00 to FEF8 mapped to internal ROM. This ROM contains the startup code for the Atari Lynx. The startup vector for the Lynx is hardcoded to be $FF80 inside the boot ROM code. The ROM will perform a number of steps to start and initialize the Lynx and load a cartridge and start the program or game that is on it.
- Turn cartridge power off
- Erase RAM memory to zeros (
0x00) - Initialize Mikey (see table below).
Effectively it sets the timers for horizontal and vertical scans, and loads the palette with black and yellow
| Address | Name | Value | Symbol |
|---|---|---|---|
| FD90 | SDONEACK | 00 | Acknowledge Suzy |
| FD92 | DISPCTL | 0D | 4 bit color with video DMA enabled |
| FD95 | DISPADRH | 20 | Video address at 0x0200 |
| FD94 | DISPADRL | 00 | |
| FD93 | PBCKUP | 29 | Magic P value for screen frequency |
| FD09 | TIM2CTLA | 1F | |
| FD08 | TIM2BCKUP | 68 | Backup value of 104 for 102 LCD lines and 3 overscan lines |
| FDBF | BLUEREDF | 3E | Yellow |
| FDAF | GREENF | 0E | Yellow |
| FDB0 | BLURED0 | 00 | Black |
| FDA0 | GREEN0 | 00 | Black |
| FD01 | TIM0CTLA | 18 | 2 microseconds timing for horizontal line (60Hz) |
| FD00 | TIM0BCKUP | 9E | 1 |
If during the boot process there turns out to be something wrong with the bootloader or cartridge contents, the Lynx will not start up correctly. It will either freeze or display an “INSERT GAME” message on screen.
You can see that the yellow and black color are used to display the text of the message.
- Cartridge not inserted: Static
INSERT GAMEdisplayed - Decryption failure: fast flashing
INSERT GAME - Hash value mismatch of cartridge contents: Lynx freezes