AS8218_1 Datasheet, PDF (96/123 Pages) ams AG – Highly Integrated Single Phase 2 Current Energy Metering Integrated Circuits

Data Sheet AS8218 / AS8228
There are five special function registers (SFR) related to the Timer 0:
Register Name Address Description
TMOD
89h
Timer mode register
TCON
88h
Timer control register
T0PRE
8Eh
Timer 0 8 bit prescaler register
TH0
8Ch
Timer 0 higher byte
TL0
8Ah
Timer 0 lower byte
TMOD
MSB
LSB
0
0
0
0
GATE
C/T_N
M1
M0
Bit Symbol Function
7
- Not used
6
- Not used
5
- Not used
4
- Not used
3 GATE Has no effect on Timer 0 operation can be used as register bit
2 C/T_N ^{Acts like an enable signal}
Mode Description
Bit1 Bit0
1
M1
0 13 bit timer (MCS-48 compatible)
0
0
Mode select
1 Same as mode 0 but 16 bit timer
0
1
2 Configures Timer 0 as 8 bit autoreload timer. Overflow from
1
0
0
M0
TL0 sets TF0 and reloads TL0 with the value of TH0.
3 Two 8 bit timers, TL0 controlled by Timer 0 standard bits,
1
1
TH0 controlled by Timer 1 control bits but no interrupt
TCON
MSB
LSB
TF1
TR1
TF0
TR0
-
-
-
-
Bit Symbol Function
7
TF1 Timer 0 (Mode 3) TH0 overrun flag, generates no interrupt, flag can be polled by software.
6
TR1 Timer 0 (Mode 3) TH0 enable flag, TH0 runs if ‘1’ in all other modes the flag has no effect.
5
TF0 Timer 0 overrun flag, generates an interrupt. Flag is cleared by hardware when the processor jumps to
the interrupt routine
4
TR0 Timer 0 run control bit. Timer runs if ‘1’. Cleared/set by software.
3
- Not used
2
- Not used
1
- Not used
0
- Not used
Revision 3.0, 31-May-06
Page 96 of 123