I/O Map
The following table lists the main I/O definitions of the Cosmac Elf 2000 and additional HW. Note that I/O would off course only work if specified HW is connected. This is a summary for all details please see the Elf 2000 manual available from the Cosmac Elf 2000 Spare Time Gizmos site.
| Q |
- GPIO (General Purpose I/O Card): if defined switch on/off default tone - Video Terminal: serial output |
| EF1 |
- TVB (80 Column Text Video Board): vertical retrace - CDP 1861 display: display status |
| EF2 | GPIO: PS2 Keyboard data ready flag |
| EF3 | Video Terminal: serial input |
| EF4 | If EF4=0 IN button is pressed |
| OUT 1 |
- TVB: write intel 8275 parameter - CDP 1861 display: display off |
| OUT 2 | Disk/UART/RTC: device/register selection |
| OUT 3 | Disk/UART/RTC: write in selected device/register |
| OUT 4 | TIL 311 data display |
| OUT 5 | TVB: write intel 8275 command register |
| OUT 7 | GPIO: write control register |
| INP 1 |
- TVB: read intel 8275 paramter - CDP 1861 display: display on |
| INP 2 | Reserved for expansion card |
| INP 3 | Disk/UART/RTC: read status |
| INP 4 | Hex panel or switch panel input |
| INP 5 | TVB: read intel 8275 status register |
| INP 6 | GPIO: read PS2 Keyboard data |