364
CY8C28xxx PSoC Programmable System-on-Chip TRM, Document No. 001-52594 Rev. *G
Digital Blocks
Figure 17-10. Last-shot meets IOW
If the ENCLR and IOW enable occur simultaneously, the
system IOW enable has higher priority. However if the
ENCLR and IOW disable occur simultaneously, ENCLR
takes over, shown as shown in
In the special case when DR1 is zero, the function is not in
multi-shot mode, whether or not the multi-shot period regis-
ter in CR1 is written zero. Therefore the minimal count
period in multi-shot mode is two cycles.
KILL Disable Operation.
In KILL-Disable mode, the KILL
signal is first synchronized at the falling edge of SYSCLK,
and then the synchronized KILL is used to clear EN bit. Syn-
chronizing at the falling edge of SYSCLK allows for a safe
timing window if an IOW enable follows the kill signal. Note
that the block outputs are immediately asserted low at
detection of a kill signal.
Figure 17-11. KILL-Disable and IOW Timing
KILL Reload Operation.
In KILL-Reload mode, the KILL
signal is synchronized at the rising edge of block clock and
is extended one block clock cycle. DR0 reloads at rising
edge of the block clock when KILL-synced is high. The multi-
shot counter reloading occurs at rising edge of the block
clock after KILL-synced is released.
Figure 17-12. KILL-Reload Timing
Multi-Block Terminal Count/Compare Operation.
When
timers are chained, the CO signal of a given block becomes
the Carry In (CI) of the next most significant block in the
chain. In a chained timer, the CO output indicates that the
block and all lower blocks are at 00h count. The CO is set up
to the next positive edge of the clock, to enable the next
higher block to count once for every Terminal Count (TC) of
all lower blocks.
The terminal count out of a given block becomes the termi-
nal count in of the next least significant block in the chain.
The terminal count output indicates that the block and all
higher blocks are at 00h count. The terminal count in/termi-
nal count out chaining signals provide a way for the lower
blocks to know when the upper blocks are at TC. Reload
occurs when all blocks are at TC, which can be determined
by CI, terminal count in, and the block zero detect. Example
timing for a three block timer is shown in
The compare circuit compares registers DR0 <= DR2.
(When Mode[1] = 1, the comparison is DR0 < DR2.)
Each block has an internal compare condition (DR0 com-
pared to DR2), a chaining signal to the next block called
CMPO, and the chaining signal from the previous block
called CMPI. In any given block of a timer, the CMPO is
used to generate the auxiliary output (primary output in the
counter) with a one cycle clock delay.
CLK
DR0
Multi-Shot Counter
Last-Shot
EN
ENCLR (internal)
CMP OUT
IOW_
0
N
1
1
0
IOW disable
Last shot takes
over the control
0
N
1
1
0
IOW enable
IOW enable takes
over the control
N-1
N-2
M
CLK
DR0
Multi-Shot Counter
Last-Shot
EN
ENCLR (internal)
CMP OUT
IOW_
SYSCLK
EN
IOW_
IOW enable
KILL
KILL-Synced
Block Ouput
Block Clock
DR0
Multi-Shot Counter
KILL
KILL-Synced
X
N
N-1
X
M
N
If wrong data is registered, it does not
affect multi-shot counter.
Содержание CY8C28 series
Страница 65: ...64 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G RAM Paging ...
Страница 85: ...84 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Internal Main Oscillator IMO ...
Страница 93: ...92 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G External Crystal Oscillator ECO ...
Страница 97: ...96 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Phase Locked Loop PLL ...
Страница 125: ...124 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G ...
Страница 311: ...310 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G IDAC_CR0 1 FDh ...
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Страница 425: ...424 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Analog Reference ...
Страница 461: ...460 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Two Column Limited Analog System ...
Страница 477: ...476 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Digital Clocks ...
Страница 483: ...482 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Multiply Accumulate MAC ...
Страница 513: ...512 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Internal Voltage Reference ...
Страница 523: ...522 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Switch Mode Pump SMP ...
Страница 533: ...532 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G I O Analog Multiplexer ...
Страница 537: ...536 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G Real Time Clock RTC ...
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