SST89V54RD2 Silicon Storage Technology, Inc., SST89V54RD2 Datasheet - Page 51

• Manufacturer Part Number: SST89V54RD2
• Description: Flashflex51 Mcu
• Manufacturer: Silicon Storage Technology, Inc.

FlashFlex MCU
SST89V54RD2/RD / SST89V58RD2/RD
8.3.3 High Speed Output Mode
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.
©2007 Silicon Storage Technology, Inc.
Write to
CCAPnH
FIGURE
1
CCAPnL
Write to
8-4: PCA High Speed Output Mode
0
Reset
Enable
CCAPnH
PCA Timer/Counter
16-bit Comparator
CH
CF
CCAPnL
ECOMn CAPPn CAPNn MATn
CR
CL
0
51
Match
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)
CCF4
0
CCF3
CCF2
TOGn
PWMn ECCFn
CCF1
0
CCF0
Toggle
CCAPMn
CCON
S71255-10-000
n=0 to 4
1255 F26.0
PCA Interrupt
Data Sheet
CEXn
12/07