PC87393VJG National Semiconductor, PC87393VJG Datasheet - Page 101

• Manufacturer Part Number: PC87393VJG
• Description: IC, SUPER I/O DEVICE, TQFP-100
• Manufacturer: National Semiconductor

Specifications of PC87393VJG

• Data Rate: 2Mbps
• Supply Voltage Range: 3V to 3.6V
• Logic Case Style: TQFP
• No. Of Pins: 100
• Operating Temperature Range: 0°C to +70°C
• Termination Type: SMD
• Transceiver Type: Interface
• Rohs Compliant: No

6.0 Musical Instrument Digital Interface (MIDI) Port
6.2.9
The MIDI Port supports the following modes/operations, which are not part of the Legacy definition of the MIDI Port:
Transmit in Pass-Thru. When the MIDI Port is operated in Pass-Thru mode, transmit is disabled by default. To enable it,
write 1 to bit 4 of the MCNTL register.
Loopback Mode. The MIDI serial data transmit signal is routed internally to the MIDI serial data receive signal. This causes
all the data transmitted by the MIDI Port to also be received. Loopback mode can be used as a mode for testing the MIDI
Port or its software. To enable it, write 1 to bit 7 of the MCNTL register.
MIDI Thru. The MIDI serial data receive signal is routed internally to the MIDI serial data transmit signal. This causes any
incoming stream of pulses received via the MDRX pin to be driven immediately on the MDTX pin. This feature allows the
MIDI Port to be connected as a link in a chain of several MIDI devices. In parallel to routing the MIDI receive signal to the
MIDI transmit signals, the incoming serial data is also received by the MIDI Port itself. To enable it, write 1 to bit 6 of the
MCNTL register.
MDTX Pin Masking. MDTX pin masking forces this pin to remain at a high level. This causes all transmit processes to occur
without physically driving the serial data via the MDTX pin. Writing 1 to bit 2 of the MCNTL register enables MDTX pin mask-
ing.
The above three features are handled by the MIDI Signals Routing Control Logic, which is illustrated in Figure 20.
Transmit in Pass-Thru
Loopback mode
MIDI Thru
MDTX pin masking
Enhanced MIDI Port Features
Transmit
MIDI
Signal
MIDI
Receive
Signal
Figure 20. MIDI Signals Routing Control Logic
Loopback
Enable
Mode
1
0
MIDI Thru
Enable
101
0
1
MDTX Pin
Masking
Enable
(Continued)
MDTX Pin
MDRX Pin
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