MT9094 Mitel Networks Corporation, MT9094 Datasheet - Page 12

• Manufacturer Part Number: MT9094
• Description: ISO2-CMOS ST-BUS FAMILY Digital Telephone (DPhone-II)
• Manufacturer: Mitel Networks Corporation

MT9094
Watchdog
To maintain program integrity an on-chip watchdog
timer
microcontroller reset pin. The watchdog output WD
(pin 17) goes high while the DPhone-II is held in
reset via the PWRST (pin 6). Release of PWRST will
cause WD to return low immediately and will also
start the watchdog timer. The watchdog timer is
clocked on the falling edge of F0i and requires only
this input, along with V
If the watchdog reset word is written to the watchdog
register (address 11h) after PWRST is released, but
before the timeout period (T=512mSec) expires, a
reset of the timer results and WD will remain low.
Thereafter, if the reset word is loaded correctly at
intervals less than 'T' then WD will continue low. The
first break from this routine, in which the watchdog
register is not written to within the correct interval or
it is written to with incorrect data, will result in a high
going WD output after the current interval 'T' expires.
7-56
Address
17-1C
27-3F
00-09
(Hex)
0A
0B
0C
0D
0E
1D
1E
0F
10
12
13
14
15
16
1F
20
21
22
23
24
25
26
11
is
provided
TONE RINGER WARBLE RATE REGISTER
FCODEC GAIN CONTROL REGISTER 1
FCODEC GAIN CONTROL REGISTER 2
LCD SEGMENT ENABLE REGISTER 1
LCD SEGMENT ENABLE REGISTER 2
RECEIVE GAIN CONTROL REGISTER
TRANSDUCER CONTROL REGISTER
TRANSMIT AUDIO GAIN REGISTER
TRANSMIT DTMF GAIN REGISTER
TONE COEFFICIENT REGISTER 1
TONE COEFFICIENT REGISTER 2
C-CHANNEL REGISTER (to DSTo)
DD
GENERAL CONTROL REGISTER
TIMING CONTROL REGISTER
for
, for operation.
DSP CONTROL REGISTER
WATCHDOG REGISTER
LOOP-BACK REGISTER
connection
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
WRITE
DPhone-II Register Map
to
the
WD will then toggle at this rate until the watchdog
register is again written to correctly.
x=don’t care
Test Loops
Detail LBio and LBoi Loopback Register (address
16h)
LBio
LBoi
5-BIT WATCHDOG RESET WORD
X
X
C-CHANNEL REGISTER (from DSTi)
Setting this bit causes data on DSTi to
be looped back to DSTo directly at the
pins. The appropriate channel enables
Ch
Setting this bit causes data on DSTo to
be looped back to DSTi directly at the
pins.
1
X
EN -Ch
W4
0
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
3
NOT USED
EN must also be set.
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
VERIFY
READ
W3
1
W2
0
W1
1
W0
0