msm7715 Oki Semiconductor, msm7715 Datasheet - Page 16

• Manufacturer Part Number: msm7715
• Description: Multi-function Telecommunication Lsi
• Manufacturer: Oki Semiconductor

¡ Semiconductor
Microcontroller interface
By externally connecting DT1 to DT4 and DTG1 to DTG4 respectively, a 4-bit bus can be
configured (Fig 9).
In DTMF signal transmit mode, DT1 to DT4 enter a high-impedance state and this 4-bit line is
used to set the DTMF code against DTG1 to DTG4. The bus data is latched at the falling edge of
TEN.
In DTMF signal receive mode, DT1 to DT4 enter an output state. The 4-bit bus line is used as the
output of the DTMF code from DT1 to DT4 to the microcontroller. Latch this bus data at the rising
edge of SP.
In modem mode, DT1 to DT4 enter a high-impedance state. This 4-bit bus line is pulled up by
the pull-up resistor in DTG1 to DTG4.
In power-down mode (PON = "1"), DT1 to DT4 enter a high-impedance state. Since the pull-up
resistors in DTG1 to DTG4 also enter a high-impedance state, potential of this 4-bit bus line
becomes unstable from the MSM7715.
Microcontroller
Figure 9 Microcontroller Interface Example
DTG1
DTG2
DTG3
DTG4
DT1
DT2
DT3
DT4
DTMF Generator
DTMF Receiver
MSM7715
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