diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/api-asm.68k | 33 | ||||
| -rw-r--r-- | doc/api-c.txt | 35 |
2 files changed, 66 insertions, 2 deletions
diff --git a/doc/api-asm.68k b/doc/api-asm.68k index e6f466c..ad552f3 100644 --- a/doc/api-asm.68k +++ b/doc/api-asm.68k @@ -88,6 +88,31 @@ Echo_GetStatus ============================================================================= +*** Settings *** + +Echo_SetPCMRate + + Changes the sample rate of PCM. Note this is a global parameter as it + affects both BGM and SFX. The value is what one would write in timer A of + the YM2612 register. Here are the approximate frequencies for some values + (default is $05): + + NTSC PAL | NTSC PAL + ----------------------------|-------------------------- + $02 ... 26632Hz ... 26389Hz | $08 ... 6658Hz ... 6597Hz + $03 ... 17755Hz ... 17593Hz | $09 ... 5918Hz ... 5864Hz + $04 ... 13316Hz ... 13194Hz | $0A ... 5326Hz ... 5278Hz + $05 ... 10653Hz ... 10556Hz | $0B ... 4842Hz ... 4798Hz + $06 .... 8877Hz .... 8796Hz | $0C ... 4439Hz ... 4398Hz + $07 .... 7609Hz .... 7539Hz | $0D ... 4097Hz ... 4060Hz + + The higher the sample rate, the better quality, but also takes up more + space and, more importantly, reduces CPU time available for other things + (which can hamper Echo's ability to process complex streams). Be careful + if you increase the sample rate. + +============================================================================= + *** Raw access *** Echo_SendCommand @@ -95,10 +120,16 @@ Echo_SendCommand Sends an argument-less command to Echo. The command ID is given as a byte in register d0. -Echo_SendCommandEx +Echo_SendCommandAddr Sends a command to Echo that takes an address as its argument. The command ID is given as a byte in register d0, while the address argument is given in register a0. +Echo_SendCommandByte + + Sends a command to Echo that takes a byte as its argument. The command ID + is given as a byte in register d0, while the byte argument is given in + register d1. + ============================================================================= diff --git a/doc/api-c.txt b/doc/api-c.txt index fcfd07b..a248051 100644 --- a/doc/api-c.txt +++ b/doc/api-c.txt @@ -92,6 +92,31 @@ uint16_t echo_get_status() ============================================================================= +*** Settings *** + +void echo_set_pcm_rate(uint8_t rate) + + Changes the sample rate of PCM. Note this is a global parameter as it + affects both BGM and SFX. The value is what one would write in timer A of + the YM2612 register. Here are the approximate frequencies for some values + (default is 0x05): + + NTSC PAL | NTSC PAL + -----------------------------|--------------------------- + 0x02 ... 26632Hz ... 26389Hz | 0x08 ... 6658Hz ... 6597Hz + 0x03 ... 17755Hz ... 17593Hz | 0x09 ... 5918Hz ... 5864Hz + 0x04 ... 13316Hz ... 13194Hz | 0x0A ... 5326Hz ... 5278Hz + 0x05 ... 10653Hz ... 10556Hz | 0x0B ... 4842Hz ... 4798Hz + 0x06 .... 8877Hz .... 8796Hz | 0x0C ... 4439Hz ... 4398Hz + 0x07 .... 7609Hz .... 7539Hz | 0x0D ... 4097Hz ... 4060Hz + + The higher the sample rate, the better quality, but also takes up more + space and, more importantly, reduces CPU time available for other things + (which can hamper Echo's ability to process complex streams). Be careful + if you increase the sample rate. + +============================================================================= + *** Raw access *** void echo_send_command(uint8_t command) @@ -103,7 +128,7 @@ void echo_send_command(uint8_t command) ECHO_CMD_RESUMEBGM ... Resume background music playback ECHO_CMD_STOPSFX ..... Stop sound effect playback -void echo_send_command_ex(uint8_t command, const void *address) +void echo_send_command_addr(uint8_t command, const void *address) Sends a command to Echo that takes an address as its argument. The parameter 'command' is the command to send, while the parameter 'address' @@ -117,4 +142,12 @@ void echo_send_command_ex(uint8_t command, const void *address) makes Echo load the instrument list by itself and it expects a different format from the one used by the C API. +void echo_send_command_byte(uint8_t command, uint8_t byte) + + Sends a command to Echo that takes a byte as its argument. The parameter + 'command' is the command to send, while the parameter 'byte' is the byte + to use as argument. The command may be... just this for now: + + ECHO_CMD_SETPCMRATE ... Change PCM sample rate + ============================================================================= |