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Monitor Lead IDs
Programmer's Reference Manuals
» Part 16 – Service Calls
» Service_MonitorLeadTranslation
» Monitor Lead IDs
Monitor Lead IDs
The monitor lead ID is an 8-bit value which is split into four 2-bit fields.
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|
| Field | ID3 | ID2 | ID1 | ID0 | ||||
The subfields correspond to the 4 ID pins that are present in the monitor lead. The value of each field indicates what that pin is connected to.
| Value | Pin tied to |
|---|---|
| 0 | 0v |
| 1 | +5v |
| 2 | Hsync |
| 3 | Indeterminate |
Notes
The version of the portable module used in the A4 recognises that 1,1,1,1 occurs when no lead is connected, and sets mode 27, type 5, sync 0.
If Service_MonitorLeadTranslation is unclaimed RISC OS recognises the following values:
| ID0 | ID1 | ID2 | ID31 | Type | Sync | Mode |
|---|---|---|---|---|---|---|
| H | +5v | +5v | n/a | 0 – TV | Composite | 12 |
| +5v | +5v | H | n/a | 1 – Multisync | Composite | 27 |
| +5v | 0v | +5v | n/a | 3 – Mono VGA | Separate | 27 |
| 0v | +5v | +5v | n/a | 3 – Colour VGA | Separate | 27 |
| 0v | +5v | 0v | n/a | 4 – SVGA | Separate | 27 |
1 Value of ID3 is not used
If even this fails, RISC OS assumes type 0 – TV standard.