MT8885 Mitel Networks Corporation, MT8885 Datasheet - Page 13

• Manufacturer Part Number: MT8885
• Description: Integrated DTMFTransceiver with Power Down & Adaptive Micro Interface
• Manufacturer: Mitel Networks Corporation

Advance Information
A software reset must be included at the beginning of all programs to initialize the control registers after
power up.
Description:
1) Read Status Register
2) Write to Control Register
3) Write to Control Register
4) Write to Control Register
5) Write to Control Register
6) Read Status Register
Transmit DTMF tones of 50 ms burst/50 ms pause and Receive DTMF Tones.
Sequence:
1) Write to Control Register A
2) Write to Control Register B
3) Write to Transmit Data Register
4) Wait for an Interrupt or Poll Status Register
5) Read the Status Register
NOTE: IN THE TX BURST MODE, STATUS REGISTER BIT 1 WILL NOT BE SET UNTIL 100 ms ( ±2 ms) AFTER THE DATA IS
WRITTEN TO THE TX DATA REGISTER. IN EXTENDED BURST MODE THIS TIME WILL BE DOUBLED TO 200 ms (± 4 ms)
(tone out, DTMF, IRQ, Select Control Register B)
(burst mode)
(send a digit 7)
-if bit 1 is set, the Tx is ready for the next tone, in which case ...
Write to Transmit Register
(send a digit 5)
-if bit 2 is set, a DTMF tone has been received, in which case ....
Read the Receive Data Register
-if both bits are set ...
Read the Receive Data Register
Write to Transmit Data Register
TYPICAL CONTROL SEQUENCE FOR BURST MODE APPLICATIONS
INITIALIZATION PROCEDURE
Figure 14 - Application Notes
RS0
RS0
1
1
1
1
1
1
1
1
0
1
0
0
0
0
Motorola
R/W
R/W
1
0
0
0
0
1
0
0
0
1
0
1
1
0
WR RD
WR RD
1
0
0
0
0
1
0
0
0
1
0
1
1
0
Intel
0
1
1
1
1
0
1
1
1
0
1
0
0
1
b3
b3
X
0
0
1
0
X
1
0
0
X
0
X
X
0
Data
b2
b2
X
0
0
0
0
X
1
0
1
X
1
X
X
1
MT8885
b1
b1
X
0
0
0
0
X
0
0
1
X
0
X
X
0
b0
b0
X
0
0
0
0
X
X
X
X
1
0
1
1
1
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