P89V51RD2 Philips Semiconductors, P89V51RD2 Datasheet - Page 44

• Manufacturer Part Number: P89V51RD2
• Description: 8-bit 80C51 5 V low power 64 kB Flash microcontroller with 1 kB RAM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 12964
Product data
Fig 20.
Module functions:
16-bit capture
16-bit timer
16-bit high speed output
8-bit PWM
Watchdog timer (Module 4 only)
time base for PCA modules
PCA TIMER/COUNTER
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 (CCF4:0). 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.
The TOG bit (CCAPMn.2) when set causes the CEX output associated with the
module to toggle when there is a match between the PCA counter and the module’s
capture/compare register.
The match bit MAT (CCAPMn.3) when set will cause the CCFn bit in the CCON
register to be set when there is a match between the PCA counter and the module’s
capture/compare register.
16 bits
Rev. 01 — 01 March 2004
MODULE0
MODULE1
MODULE2
MODULE3
MODULE4
16 bits
8-bit microcontrollers with 80C51 core
Figure
Figure
P1.3/CEX0
P1.4/CEX1
P1.5/CEX2
P1.6/CEX3
P1.7/CEX4
21.
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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