Alarms
Pocket Family GB provides an alarm feature through the HuC-3 mapper, with a selection of different alarm tones. It also supports installing additional alarm tones through GBKiss.
Format
Downloadable alarm tones are GBKiss data files with the following sections:
| Section | Size |
| Metadata | Variable |
| Name length | 1 |
| Name | 1-8? |
| Pattern length | 1 |
| Pattern | 1-255? |
The alarm tone’s name may differ from the file name; the file name is shown in GBKiss, while the tone name is shown within the Pocket Family GB settings menu.
Need verification:
- What is the maximum file name that can be shown?
- What happens if the displayable length is exceeded?
- What is the maximum pattern length?
- What happens on invalid patterns?
Pattern
Patterns consist of:
- 1 unidentified bytes (always observed to be $40)
- 1 tempo command? (observed $Fx and $Cx)
- 1 transpose command (often $A7)
- Body commands
- 1 end pattern command ($B0)
The following commands are hypothesized:
| Cmd | Meaning | Argument |
| $0x | Sixteenth note? | Pitch offset (semitones) |
| $1x | Eighth note | Pitch offset (semitones) |
| $2x | Dotted eighth note? | Pitch offset (semitones) |
| $3x | Quarter note | Pitch offset (semitones) |
| $4x | Dotted quarter note | Pitch offset (semitones) |
| $5x | Half note | Pitch offset (semitones) |
| $6x | Dotted half note | Pitch offset (semitones) |
| $7x | Whole note? | Pitch offset (semitones) |
| $8x | Rest | 0-8, matching note length? |
| $Ax | Transpose | Offset |
| $B0 | End pattern | Always 0 |
The pitch of each note is determined by adding the note’s pitch offset to twice the current transposition and interpreting it as a number of semitones. In the common transposition $A7, pitch $1 is C4. Thus, the total pitch range is A2 (0) to F♯6 (45). Alternately, to map to a MIDI pitch number, add 47 (A2).
Some of the built-in tones, such as Alarm 2, demonstrate volume control.
Notes
Not all alarm tones appear to be programmed like this. Pocket Family GB has three blocks in its ROM that look like alarm tones. The first is Afterschool chime; the second Silent Night; and the third appears incomplete and unused:
07:5c40: 465c 985c 5b5c F\.\[\
5c46: 1440 c2a7 3a36 3861 3138 .@..:68a18
07:5c50: 3a76 83b0 0000 0000 0001 f6 :v.........
5c5b: 3c 4029 a748 <@).H
07:5c60: 1a38 6548 1a38 655f 3f6c 5d3d 685a 3a4d .8eH.8e_?l]=hZ:M
07:5c70: 1c3a 481a 3865 5a3a 4d1c 3a48 1a38 65ad .:H.8eZ:M.:H.8e.
07:5c80: 5333 4613 3061 65a7 3d38 3548 1633 3135 S3F.0ae.=85H.315
07:5c90: 387d b000 0000 03f6
5c98: 10c6 d9a8 4243 b0dd 8}..........BC..
07:5ca0: d300 0000 0000 0000 f6 .........
5ca9: