IA8044/IA8344
Data Sheet
SDLC Communications Controller
March 30, 2010
Bit [2]—C/T → (TMOD.2) C/T selects Timer 0 or Counter 0 operation. When set to 1, the
counter operation is performed. When cleared to 0, the register will function as a timer.
Bit [1]—M1 → (TMOD.1) Timer 0 mode selector bit.
Bit [0]—M0 → (TMOD.0) Timer 0 mode selector bit.
Table 16. Timer Mode Select Bits
M1 M0
Operating Mode
0
0
1
1
0
1
0
1
0
1
2
3
13-bit timer
16-bit timer/counter
8-bit auto-reload timer/counter
Timer 0–TL0 is a standard 8-bit timer/counter controlled by Timer 0 control bits. TH0 is an
8-bit timer function only, controlled by Timer 1 control bits.
1
1
3
Timer/Counter 1 stopped and holds its count. Can be used to start/stop Timer 1 when
Timer 0 is in Mode 3.
4.7.7 Timer Control (TCON)
Table 17 presents the timer control register, which provides control bits that start and stop the
counters. It also contains bits to select the type of external interrupt desired, edge or level.
Additionally, TCON contains status bits showing when a timer overflows and when an interrupt
edge has been detected.
Table 17. Timer Control Register
7
6
5
4
3
2
1
0
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Bit [7]—TF1 → (TCON.7) Timer 1 overflow flag set by hardware when Timer 1
overflows. This flag should be cleared by software. In Mode 3 this bit is controlled by
TH0.
Bit [6]—TR1 → (TCON.6) Timer 1 run control bit. If cleared, Timer 1 stops. In Mode 3
this bit controls TH0.
Bit [5]—TF0 → (TCON.5) Timer 0 overflow flag set by hardware when Timer 0
overflows. This flag should be cleared by software.
Bit [4]—TR0 → (TCON.4) Timer 0 run control bit. If cleared, Timer 0 stops.
Bit [3]—IE1→ (TCON.3) Interrupt 1 edge flag. Set by hardware, when falling edge on
external pin INT1 is detected cleared when interrupt is processed.
®
IA211010112-04
UNCONTROLLED WHEN PRINTED OR COPIED
http://www.Innovasic.com
Customer Support:
Page 28 of 65
1-888-824-4184
INNOVASIC [ INNOVASIC, INC ]
