Rainbow Electronics T89C51CC01 - Manual (Page 111)

111
T89C51CC01
Rev. D – 17-Dec-01
Figure 42. PCA Capture Mode
16.5 16-bit Software
Timer Mode 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.
Figure 43. PCA 16-bit Software Timer and High Speed Output Mode
CEXn
n = 0, 4
PCA Counter
CH
(8bits)
CL
(8bits)
CCAPnH CCAPnL
CCFn
CCON
PCA
Interrupt
Request
- 0CAPPnCAPNn000ECCFn
7
CCAPMn Register (n = 0, 4)
0
CCAPnL
(8 bits)
CCAPnH
- ECOMn0 0 MATn TOGn0 ECCFn
7 0
CCAPMn Register
(n = 0, 4)
CH
(8 bits)
CL
(8 bits)
16-Bit Com-
parator
Match
Enable
CCFn
CCON reg
PCA
Interrupt
Request
CEXn
Compare/Capture Module PCA Counter
“0”
“1”
Reset
Write to
CCAPnL
Write to CCAPnH
For software Timer mode, set ECOMn and MATn.
For high speed output mode, set ECOMn, MATn and TOGn.
Toggle