p89cv51rb2 NXP Semiconductors, p89cv51rb2 Datasheet - Page 42

• Manufacturer Part Number: p89cv51rb2
• Description: P89cv51rb2/rc2/rd2 8-bit 80c51 5 V Low Power 64 Kb Flash Microcontroller With 1 Kb Ram, Spi, 6-clock Cpu With 6/12-clock Peripherals
• Manufacturer: NXP Semiconductors

NXP Semiconductors
P89CV51RB2_RC2_RD2_1
Product data sheet
to CEX0, module 1 to CEX1, etc. Registers CH and CL contain the current value of the
free-running up-counting 16-bit PCA timer. The PCA timer is a common time base for all
five modules and can be programmed to run at:
oscillator frequency, the Timer 0 overflow, or the input on the ECI pin (P1[2]). The timer
count source is determined from the CPS1 and CPS0 bits in the CMOD SFR; see
Table 32
In the CMOD SFR there are three additional bits associated with the PCA. They are CIDL
which allows the PCA to stop during Idle mode, WDTE which enables or disables the
watchdog function on module 4, and ECF which when set causes an interrupt and the
PCA overflow flag CF (in the CCON SFR) to be set when the PCA timer overflows.
The watchdog timer function is implemented in module 4 of PCA.
The CCON SFR contains the run control bit for the PCA (CR) and the flags for the PCA
timer (CF) and each module (CCF[4:0]). To run the PCA the CR bit (CCON.6) must be set
by software. The PCA is shut off by clearing this bit. The CF bit (CCON.7) is set when the
PCA counter overflows and an interrupt will be generated if the ECF bit in the CMOD
register is set. The CF bit can only be cleared by software. Bits 0 through 4 of the CCON
register are the flags for the modules (bit 0 for module 0, bit 1 for module 1, etc.) and are
set by hardware when either a match or a capture occurs. These flags can only be cleared
by software. All the modules share one interrupt vector. The PCA interrupt system is
shown in
Each module in the PCA has a special function register associated with it. These registers
are: CCAPM0 for module 0, CCAPM1 for module 1, etc. The registers contain the bits that
control the mode that each module will operate in.
The ECCF bit (from CCAPMn.0 where n = 0, 1, 2, 3, or 4 depending on the module)
enables the CCFn flag in the CCON SFR to generate an interrupt when a match or
compare occurs in the associated module; see
PWM (CCAPMn.1) enables the Pulse-width modulation mode.
Fig 19. PCA
time base for PCA modules
Module functions:
- 16-bit capture
- 16-bit timer
- 16-bit high speed output
- 8-bit PWM
- watchdog timer (module 4 only)
and
Figure
PCA TIMER/COUNTER
Table
16 bits
20.
33.
Rev. 01 — 5 October 2007
P89CV51RB2/RC2/RD2
Figure
1
6
MODULE3
MODULE4
MODULE0
MODULE1
MODULE2
the oscillator frequency,
16 bits
20.
80C51 with 1 kB RAM, SPI
© NXP B.V. 2007. All rights reserved.
P1[3]/CEX0
P1[4]/CEX1
P1[5]/CEX2
P3[4]/T0/CEX3
P3[5]/T1/CEX4
1
002aab913
2
the
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