CALL PCMREC - MSX Wiki

1 Effect
2 Syntaxes
3 Parameters
4 Example
5 Related to
6 Compatibility

Effect

Records a PCM audio file by using the built-in microphone of the MSX Turbo R computers. It can be done to computer RAM, computer VRAM or an array.

If the computer mode is Z80 mode, the mode is automatically switched to the R800 mode before the execution, and after finishing the Z80 mode is restored.

If the STOP key is pushed during the recording, the program execution is quit and returns to BASIC.

Syntaxes

CALL PCMREC(@<StartAddress>, <EndAddress>, <SamplingFrequency>,<TriggerLevel>,<CompressionSwitch>,S)

The three last parameters are optional. Parameters can not end with a comma alone.

CALL PCMREC(<Array>,<Length>,<SamplingFrequency>,<TriggerLevel>,<CompressionSwitch>])

<Length> and the two last parameters are optional. Parameters can not end with a comma alone.

Parameters

<StartAddress> and <EndAddress> are used to specify the area of the computer RAM (or VRAM). The <start address> needs always to be preceded by @.

<SamplingFrequency> is a number between 0 and 3 to choose one of the four available sampling frequencies:

0 = 15.75 KHz
1 = 7.875 KHz
2 = 5.25 KHz
3 = 3.9375 KHz

If you specify the sampling rate to 15.75 KHz under Z80 mode or R800 ROM mode, you get "Illegal function call" error message.

<TriggerLevel> is a number between 0 and 127 to specify the required input level to start the recording. If this is omitted or is 0, the recording is started immediately.

<CompressionSwitch> allows to enable or disable the silent data compression: data format is absolutely binary and 1 to 255 is normal data. When two or more data near the 0 level (126 to 128) are consecutive, the data can be compressed by recording a 0 and count of the consecutive data.

0 (default value) = no silent data compression
1 = silent data compression

The parameter S is used to record to VRAM instead of RAM - This can be done in any screen mode but only the active pages are valid when the screen mode is higher than 4.

<Array> must be a numeric type variable array .

<Length> can generally be omitted. When specified, the recording to an array will be stopped when this length is reached.

Note: To save the PCM audio file to disk, you need to use BSAVE when you have recorded it to computer RAM or VRAM, or COPY when you have recorded it to an array.

Example

10 CLEAR 300,&HB000
20 CALL PCMREC(@&HB000,&HDFFF,1,32,1)
30 BSAVE"PCMTEST.BIN",&HB000,&HDFFF

Related to

BSAVE, CALL PCMPLAY, COPY

Compatibility

MSX-BASIC 4.0 or higher

Retrieved from "https://www.msx.org/wiki/CALL_PCMREC"

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