PCA Interrupt
Figure 33. PCA Interrupt System
CCON
0xD8
CF
CR
CCF1 CCF0
PCA Timer/Counter
Module 0
Module 1
To Interrupt
ECF
CMOD.0
EA
IEN0.7
EC
IEN0.6
ECCFn
CCAPMn.0
PCA Capture Mode
To use one of the PCA modules in 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 module
(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 reg-
isters (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.
Figure 34. PCA Capture Mode
PCA Counter
CH
CL
(8-bits)
(8-bits)
CEXn
n = 0, 1
CCAPnL
CCAPnH
PCA
Interrupt
Request
CCFn
CCON Reg
-
0CAPPnCAPNn000ECCFn
0
CCAPMn Register (n = 0, 1)
74
AT89C5115
4128F–8051–05/06
ATMEL [ ATMEL ]
