Datasheet

61
4337K–USB–04/08
AT89C5130A/31A-M
Reset Value = 000X 0000b
Not bit addressable
The watchdog timer function is implemented in module 4 (See Figure 14-4).
The PCA interrupt system is shown in Figure 14-2.
Figure 14-2. PCA Interrupt System
PCA Modules: each one of the five compare/capture modules has six possible functions. It can
perform:
• 16-bit capture, positive-edge triggered
• 16-bit capture, negative-edge triggered
• 16-bit capture, both positive and negative-edge triggered
• 16-bit Software Timer
• 16-bit High-speed Output
• 8-bit Pulse Width Modulator
In addition, module 4 can be used as a Watchdog Timer.
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. (see Table 14-3). The registers contain the
bits that control the mode that each module will operate in.
1 CCF1
PCA Module 1 Interrupt Flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
0 CCF0
PCA Module 0 Interrupt Flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
Bit
Number
Bit
Mnemonic Description
CF CR
CCON
0xD8
CCF4 CCF3 CCF2 CCF1 CCF0
Module 4
Module 3
Module 2
Module 1
Module 0
ECF
PCA Timer/Counter
ECCFn
CCAPMn.0CMOD.0
IE.6 IE.7
To Interrupt
priority decoder
EC EA