AT89C5131-PLTIL ATMEL Corporation, AT89C5131-PLTIL Datasheet - Page 61

• Manufacturer Part Number: AT89C5131-PLTIL
• Description: 8-bit Flash Microcontroller with Full Speed USB Device
• Manufacturer: ATMEL Corporation

PCA Capture Mode
Figure 27. PCA Capture Mode
16-bit Software
Timer/Compare Mode
4136B–USB–09/03
Cex.n
CF
ECOMn
CR
Table 56. CL Register
CL - PCA Counter Register Low (0E9h)
Reset Value = 0000 0000b
Not bit addressable
To use one of the PCA modules in the capture mode either one or both of the CCAPM
bits CAPN and CAPP for that module must be set. The external CEX input for the mod-
ule (on port 1) is sampled for a transition. When a valid transition occurs the PCA
hardware loads the value of the PCA counter registers (CH and CL) into the module’s
capture registers (CCAPnL and CCAPnH). If the CCFn bit for the module in the CCON
SFR and the ECCFn bit in the CCAPMn SFR are set then an interrupt will be generated
(see Figure 27).
The PCA modules can be used as software timers by setting both the ECOM and MAT
bits in the modules CCAPMn register. The PCA timer will be compared to the module’s
capture registers and when a match occurs an interrupt will occur if the CCFn (CCON
SFR) and the ECCFn (CCAPMn SFR) bits for the module are both set (see Figure 28).
Number
7 - 0
Bit
CAPPn
7
-
CAPNn MATn TOGn PWMn ECCFn
CCF4 CCF3 CCF2 CCF1 CCF0
Mnemonic
Bit
6
-
-
Description
PCA Counter
CL Value
Capture
5
-
4
-
CCAPMn, n = 0 to 4
0xDA to 0xDE
CCON
0xD8
3
CCAPnH
-
PCA Counter/Timer
CH
2
-
CCAPnL
CL
AT89C5131
1
-
PCA IT
0
-
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