LPC47M192-NW Standard Microsystems (SMSC), LPC47M192-NW Datasheet - Page 82

• Manufacturer Part Number: LPC47M192-NW
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47M192-NW

• Lead Free Status / RoHS Status: Compliant

UART MODE Command
The UART MODE command is 3Fh. The UART MODE command clears the 16C550A transmit and receive FIFOs,
places the command acknowledge byte (FEh) in the MIDI Data port receive buffer, and enables the 16C550A UART
for transmit and receive operations.
In UART mode, the MPU-401 Interface passes MIDI read and write data directly between the host (using the MIDI
Data port) and the 16C550A UART Transmit and Receive buffers.
The MPU-401 Command Controller ignores the UART MODE command when the MPU-401 Interface is already in
UART mode.
The MPU-401 RESET command is executed but not acknowledged by the MPU-401 Command Controller in UART
MODE (see Section “RESET Command”, above).
Command Acknowledge Byte
Under certain conditions, the command controller acknowledges the RESET and UART MODE commands with a
command acknowledge byte (FEh).
The command acknowledge byte appears as read-data in the MIDI Data port.
Note:
Data port. For example if the receive FIFO is not empty when an MPU-401 RESET command is received, the
command acknowledge will appear first, before any unread FIFO data. In the examples above, the receive FIFO is
cleared before the command acknowledge byte is placed in the MIDI Data port read buffer.
7.7.6 MIDI UART
Overview
The UART is used to transmit and receive MIDI protocol data from the MIDI Data port in the Host Interface (see
Section “Host Interface”).
The MIDI protocol requires 31.25k Baud (±1%) and 10 bits total per frame: 1 start bit, 8 data bits, no parity, and 1
stop bit. For example, there are 320 microseconds per serial MIDI data byte. MIDI data is transferred LSB first
(Figure 7).
The UART is configured in full-duplex mode for the MPU-401 MIDI Interface, with 16-byte send/receive FIFOs.
Note
7.7.7 MPU-401 CONFIGURATION REGISTERS
The LPC47M192 configuration registers are in Logical Device B (see “Configuration” section). The configuration
registers contain the MPU-401 Activate, Base Address and Interrupt select. The defaults for the Base Address and
Interrupt Select configuration registers match the MPU-401 factory defaults.
SMSC DS – LPC47M192
MIDI RX CLOCK
1
The command acknowledge byte will appear as the next available data byte in the receive buffer of the MIDI
MIDI RX CLOCK is the MIDI bit clock. The MIDI bit clock period is 32µs.
MIDI_IN
1
FIGURE 4 - MIDI DATA BYTE EXAMPLE
DATASHEET
Page 82
MIDI RX DATA BYTE (01H)
Rev. 03/30/05