W6691CD WINBOND [Winbond], W6691CD Datasheet - Page 80

• Manufacturer Part Number: W6691CD
• Description: ISDN S/T Interface Transceiver
• Manufacturer: WINBOND [Winbond]

8.9.2 Timer 2 TIMR2 Read/ Write Address 39H
Value after reset: 00H
TMD
0: Single Count Down mode: The timer starts when it is written a non-zero count value and stops when it
reaches zero.
1: Periodical Count Down Mode: The timer starts when it is written a non-zero count value and counts down
cyclically (periodically) with the count value.
In both cases, a maskable interrupt TIN2 is generated every time the timer reaches zero. When timer starts,
pin TOUT2 changes to HIGH and toggles every half count time. Therefore, the period of TOUT2 equals count
value.
In both cases, timer counts with the new value if it is written again before expiration.
The timer is stopped when it expires in single count mode (TMD=0), or zero count value is written in TCN5-0
(TMD=0 or 1).
TIDLE
This bit defines value of TOUT2 pin when timer is off. That is to say, the TIDLE determine the TOUT2 pin level
is high or low when timer2 is off.
TCN5-0
0: Timer is off.
1 - 63: Timer count value in unit of ms.
TMD
7
Timer 2 Mode
TIDLE
TOUT2 Idle
Timer 2 Count Value
6
TCN5
5
TCN4
4
TCN3
3
TCN2
2
80
TCN1
1
TCN0
0
Preliminary W6691
Publication Release Date: Sep 2001
Revision 1.1