t89c51rd2-slscl ATMEL Corporation, t89c51rd2-slscl Datasheet - Page 24

• Manufacturer Part Number: t89c51rd2-slscl
• Description: 0 To 40 Mhz Flash Programmable 8-bit Microcontroller
• Manufacturer: ATMEL Corporation

Figure 7. PCA Timer/Counter
24
T89C51RD2
Idle
Fosc /12
Fosc / 4
T0 OVF
P1.2
Table 10. CMOD: PCA Counter Mode Register
1.
2.
CIDL
WDTE
-
CPS1
CPS0
ECF
Address 0D9H
CIDL
Symbol
CF
CMOD
User software should not write 1s to reserved bits. These bits may be used in future 8051
family products to invoke new features. In that case, the reset or inactive value of the
new bit will be 0, and its active value will be 1. The value read from a reserved bit is
indeterminate.
f
osc
WDTE
CR
= oscillator frequency
Function
Counter Idle control: CIDL = 0 programs the PCA Counter to continue functioning during
idle Mode. CIDL = 1 programs it to be gated off during idle.
Watchdog Timer Enable: WDTE = 0 disables Watchdog Timer function on PCA Module 4.
WDTE = 1 enables it.
Not implemented, reserved for future use.
PCA Count Pulse Select bit 1.
PCA Count Pulse Select bit 0.
PCA Enable Counter Overflow interrupt: ECF = 1 enables CF bit in CCON to generate an
interrupt. ECF = 0 disables that function of CF.
CPS
1
0
0
1
1
Reset value
CCF4 CCF3 CCF2 CCF1 CCF0
CPS
0
0
1
0
1
Selected PCA input.
Internal clock f
Internal clock f
Timer 0 Overflow
External clock at ECI/P1.2 pin (max rate = f
CIDL
CPS1 CPS0
0
16 bit up/down counter
CH
WDT
osc
osc
E
0
/12 ( Or f
/4 ( Or f
(2)
ECF
osc
X
(1)
CL
-
osc
/2 in X2 Mode).
/6 in X2 Mode).
CMOD
0xD9
CCON
0xD8
X
-
overflow
To PCA
modules
X
osc
-
/ 8)
CPS1
0
It
4243G–8051–05/03
CPS0
0
ECF
0