MT8888CS Zarlink Semiconductor, Inc., MT8888CS Datasheet - Page 11

• Manufacturer Part Number: MT8888CS
• Description: DTMF Transceiver, 3.58MHz, 5V, CMOS, 20-SOIC
• Manufacturer: Zarlink Semiconductor, Inc.

A software reset must be included at the beginning of all programs to initialize the control registers after
power up.The initialization procedure should be implemented 100ms 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 (
WRITTEN TO THE TX DATA REGISTER. IN EXTENDED BURST MODE THIS TIME WILL BE DOUBLED TO 200 ms (
TEST POINT
(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
130 pF
Test load for D0-D3 pins
TYPICAL CONTROL SEQUENCE FOR BURST MODE APPLICATIONS
MMD6150 (or
equivalent)
24 kΩ
2.4 kΩ
5.0 VDC
MMD7000 (or
equivalent)
INITIALIZATION PROCEDURE
Figure 15 - Application Notes
Figure 14 - Test Circuits
RS0
RS0
1
1
1
1
1
1
1
1
0
1
0
0
0
0
Control
TEST POINT
WR
WR
1
0
0
0
0
1
0
0
0
1
0
1
1
0
RD
RD
0
1
1
1
1
0
1
1
1
0
1
0
0
1
Test load for IRQ/CP pin
±
2 ms) AFTER THE DATA IS
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
5.0 VDC
MT8888C
100 pF
3 kΩ
±
b1
b1
4 ms)
X
0
0
0
0
X
0
0
1
X
0
X
X
0
.
b0
b0
X
0
0
0
0
X
1
0
1
X
1
X
X
1
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