p87c754ebd NXP Semiconductors, p87c754ebd Datasheet - Page 12

• Manufacturer Part Number: p87c754ebd
• Description: 80c51 8-bit Microcontroller Family 4k/256 Otp/rom, Dac, Comparator, Uart, Reference
• Manufacturer: NXP Semiconductors

Philips Semiconductors
1998 Apr 23
80C51 8-bit microcontroller family
4K/256 OTP/ROM, DAC, comparator, UART, reference
NOTE:
* 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
** f
NOTE:
* 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
Symbol
CIDL
WDTE
–
CPS1
CPS0
ECF
Symbol
CF
CR
–
CCF
new bit will be 0, and its active value will be 1. The value read from a reserved bit is indeterminate.
new bit will be 0, and its active value will be 1. The value read from a reserved bit is indeterminate.
OSC
= oscillator frequency
Bit Addressable
Bit:
Bit Addressable
Bit:
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. WDTE = 1 enables it.
Not implemented, reserved for future use.*
PCA Count Pulse Select bit 1.
PCA Count Pulse Select bit 0.
CPS1
PCA Enable Counter Overflow interrupt: ECF = 1 enables CF bit in CCON to generate an interrupt. ECF = 0 disables
that function of CF.
Function
PCA Counter Overflow flag. Set by hardware when the counter rolls over. CF flags an interrupt if bit ECF in CMOD is
set. CF may be set by either hardware or software but can only be cleared by software.
PCA Counter Run control bit. Set by software to turn the PCA counter on. Must be cleared by software to turn the PCA
counter off.
Not implemented, reserved for future use*.
PCA Module interrupt flag. Set by hardware when a match or capture occurs. Must be cleared by software.
0
0
1
1
CMOD Address = OD9H
CCON Address = OD8H
CIDL
CF
7
7
CPS0
0
1
0
1
WDTE
CR
Selected PCA Input**
6
6
0
1
2
3
Figure 9. CCON: PCA Counter Control Register
Figure 8. CMOD: PCA Counter Mode Register
––
–
5
Internal clock, f
Internal clock, f
Timer 0 overflow
External clock at ECI/P3.1 pin (max. rate = f
5
CCF
–
4
4
OSC
OSC
12
12
4
––
–
3
3
CPS1
––
2
2
CPS0
OSC
––
1
1
8)
ECF
––
0
0
Reset Value = 00XX X000B
Reset Value = 00X0 0000B
83C754/87C754
Preliminary specification
SU00676A
SU00675A