PORTIBM PC Portable (uses same BIOS as XT) 0330-0331 - MPU-401 MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. UART(Universal Asyncronous Receiver/Transmitter) A peripheral device which converts a sequence of bytes into a serial bit stream at a programmable rate, and vice versa. This device is what makes an RS-232 serial port function. See also USART. Range: alternate address at PORTIBM PC Portable (uses same BIOS as XT) 0300h, occasionally at PORTIBM PC Portable (uses same BIOS as XT) 0310h or PORTIBM PC Portable (uses same BIOS as XT) 0320h 0330 RW data register 0331 R- status register (see #P0575) 0331 -W command register (see #P0576) Note: MPU-401 genarates an interrupt when MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. code is ready; by reading MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. code from the data register this interrupt is cleared Bitfields for MPU-401 status register: Bit(s) Description (Table P0575) 7 input ready =1 no data is available for reading =0 data is available for reading 6 output ready =1 not ready to receive command/data byte =0 ready to receive command/data byte 5-0 reserved Note: pending input seems to block the output SeeAlso: #P0576 (Table P0576) Values for MPU-401 commands (data go to/from PORTIBM PC Portable (uses same BIOS as XT) 0330h): Command Description Results Parameter 01h send MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. stop ACK - 02h send MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. start ACK - 03h send MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. continue ACK - 15h stop all (recording, ACK - playback and MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer.) 34h return timing bytes ACK - in stop mode 35h enable mode messages ACK - to PCIBM PC 38h enable system common ACK - messages to PCIBM PC 39h enable real time ACK - messages to PCIBM PC 3Ch use CLS sync ACK - 3Dh use SMPTE sync ACK - 3Fh enter UART(Universal Asyncronous Receiver/Transmitter) A peripheral device which converts a sequence of bytes into a serial bit stream at a programmable rate, and vice versa. This device is what makes an RS-232 serial port function. See also USART. mode ACK - 80h use MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. sync ACK - 81h use FSK sync ACK - 82h use MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. sync ACK - 83h enable metronome ACK - 84h disable metronome ACK - 87h enable pitch and ACK - controller 8Ah disable data in stopped ACK - mode 8Bh enable data in stop mode ACK - 8Ch disable measure end ACK - messages to host 91h enable ext MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. control ACK - 94h disable clock to host ACK - 95h enable clock to host ACK - 97h enable system exclusive ACK - messages to PCIBM PC ACh get MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. version ACK,VER - ADh get revision ACK,REV - Cxh set timebase to x*24 ACK - ppqn (x>1) D0h ??? ACK - DFh ??? ACK - E0h set tempo ACK BPS E4h set clocks per click ACK CPC E6h set beats per measure ACK BPM E7h send all clocks to host ACK 1 byte (04h is sent) FFh reset ACK - Notes: after receiving a command byte MPU-401 must reply with command acknowledge byte FEh in data register command parameters are sent, and response bytes are received through the data register no commands (except reset) can be issued in UART(Universal Asyncronous Receiver/Transmitter) A peripheral device which converts a sequence of bytes into a serial bit stream at a programmable rate, and vice versa. This device is what makes an RS-232 serial port function. See also USART. mode, and MPU-401 must be reset to leave UART(Universal Asyncronous Receiver/Transmitter) A peripheral device which converts a sequence of bytes into a serial bit stream at a programmable rate, and vice versa. This device is what makes an RS-232 serial port function. See also USART. mode Key: ACK command acknowledge byte (FEh) VER MIDI(Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer. version number bits 7-4: major version bits 0-3: minor version REV revision number BPS beats per second (8..250) CPC clocks per click BPM beats per measure SeeAlso: #P0576