at89c51rd2-smsum ATMEL Corporation, at89c51rd2-smsum Datasheet - Page 37

• Manufacturer Part Number: at89c51rd2-smsum
• Description: 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

4235J–8051–01/08
Table 13-1.
CMOD - PCA Counter Mode Register (D9h)
Reset Value = 00XX X000b
Not bit addressable
The CCON register contains the run control bit for the PCA and the flags for the PCA timer (CF)
and each module (Refer to Table 13-2).
• Bit CR (CCON.6) must be set by software to run the PCA. The PCA is shut off by clearing this
• Bit CF: The CF bit (CCON.7) is set when the PCA counter overflows and an interrupt will be
• Bits 0 through 4 are the flags for the modules (bit 0 for module 0, bit 1 for module 1, etc.) and
Number
bit.
generated if the ECF bit in the CMOD register is set. The CF bit can only be cleared by
software.
are set by hardware when either a match or a capture occurs. These flags also can only be
cleared by software.
CIDL
Bit
7
7
6
5
4
3
2
1
0
Mnemonic
CMOD Register
WDTE
WDTE
CPS1
CPS0
CIDL
ECF
Bit
6
-
-
-
Description
Counter Idle Control
Cleared to program the PCA Counter to continue functioning during idle Mode.
Set to program PCA to be gated off during idle.
Watchdog Timer Enable
Cleared to disable Watchdog Timer function on PCA Module 4.
Set to enable Watchdog Timer function on PCA Module 4.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
PCA Count Pulse Select
CPS1CPS0
0
0
1
1
PCA Enable Counter Overflow Interrupt
Cleared to disable CF bit in CCON to inhibit an interrupt.
Set to enable CF bit in CCON to generate an interrupt.
5
-
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
4
-
CLK PERIPH
CLK PERIPH
3
-
/6
/2
AT89C51RD2/ED2
CPS1
2
CLK PERIPH
CPS0
1
/4)
ECF
0
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