FlashFlex MCU
SST89E516RD2 / SST89E516RD
SST89V516RD2 / SST89V516RD
Data Sheet
8.3.3 High Speed Output Mode
High speed output mode is much more accurate than tog-
gling pins since the toggle occurs before branching to an
interrupt. In this case, interrupt latency will not affect the
accuracy of the output. When using high speed output,
using an interrupt is optional. Only if the user wishes to
change the time for the next toggle is it necessary to
update the compare registers. Otherwise, the next toggle
will occur when the PCA timer rolls over and matches the
last compare value. (See Figure 8-4)
The high speed output mode is used to toggle a port pin
when a match occurs between the PCA timer and the pre-
loaded value in the compare registers. In this mode, the
CEX output pin (on port 1) associated with the PCA mod-
ule will toggle every time there is a match between the PCA
counter (CH and CL) and the capture registers (CCAPnH
and CCAPnL). To activate this mode, the user must set
TOG, MAT, and ECOM bits in the module’s CCAPMn SFR.
CF
CR
CCF4 CCF3 CCF2 CCF1 CCF0
CCON
Write to
CCAPnL Reset
PCA Interrupt
Write to
CCAPnH
CCAPnH
CCAPnL
1
0
Enable
Match
16-bit Comparator
Toggle
CEXn
CH
CL
PCA Timer/Counter
CCAPMn
ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn
n=0 to 4
0
0
0
1273 F23.0
FIGURE
8-4: PCA High Speed Output Mode
©2007 Silicon Storage Technology, Inc.
S71273-03-000
1/07
52
SST [ SILICON STORAGE TECHNOLOGY, INC ]
