pca capture mode, Pca capture mode – Rainbow Electronics T89C51RD2 User Manual
Page 27
27
Rev. F - 15 February, 2001
T89C51RD2
Table 11. CCAPnH: PCA Modules Capture/Compare Registers High
Table 12. CCAPnL: PCA Modules Capture/Compare Registers Low
Table 13. CH: PCA Counter High
Table 14. CL: PCA Counter Low
6.5.1. PCA Capture Mode
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 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 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 (Refer to Figure 9).
CCAPnH Address
n = 0 - 4
CCAP0H=0FAH
CCAP1H=0FBH
CCAP2H=0FCH
CCAP3H=0FDH
CCAP4H=0FEH
7
6
5
4
3
2
1
0
Reset value
0
0
0
0
0
0
0
0
CCAPnL Address
n = 0 - 4
CCAP0L=0EAH
CCAP1L=0EBH
CCAP2L=0ECH
CCAP3L=0EDH
CCAP4L=0EEH
7
6
5
4
3
2
1
0
Reset value
0
0
0
0
0
0
0
0
CH
Address 0F9H
7
6
5
4
3
2
1
0
Reset value
0
0
0
0
0
0
0
0
CL
Address 0E9H
7
6
5
4
3
2
1
0
Reset value
0
0
0
0
0
0
0
0