362
CY8C28xxx PSoC Programmable System-on-Chip TRM, Document No. 001-52594 Rev. *G
Digital Blocks
* The UART blocks generate an SPI mode 3 style clock that is only active dur-
ing the data bits of a received or transmitted byte.
** In the SPIS, the field that is used to select the auxiliary output is used to
control the auxiliary input to select the SS_.
Bits 7 and 6: AUXCLK.
All digital block clock inputs must
be resynchronized. The digital blocks have numerous selec-
tions for clocking. In addition to the system clocks such as
VC1, VC2, and VC3, clocks generated by other digital
blocks may be selected through row or global interconnect.
To maintain the integrity of block timing, all clocks are resyn-
chronized at the input to the digital block.
The two AUXCLK bits are used to enable the input clock re-
synchronization. When enabled, the input clock is resyn-
chronized to the selected system clock, which occurs after
the 16-to-1 multiplexing. The rules for selecting the value for
this register are as follows:
■
If the input clock is based on SYSCLK (for example,
VC1, VC2, VC3 based on SYSCLK) or the output of
other blocks whose clock source is based on SYSCLK,
synchronize to SYSCLK.
■
If the input clock is based on SYSCLKX2 (for example,
VC3 based on SYSCLKX2) or another digital block
clocked by SYSCLKX2, or a SYSCLKX2 based clock,
synchronize to SYSCLKX2.
■
If you want to clock the block at 24 MHz (SYSCLK),
choose SYSCLK direct in the resynchronized bits (the
16-to-1 input clock selection is ignored).
■
If you want to clock the block at 48 MHz (SYSCLKX2),
choose SYSCLKX2 as the clock input selection and
leave the resynchronized bits in bypass mode.
The following table summarizes the available selections of
the AUXCLK bits.
Note
Selecting VC1/1 or VC2/1 (when VC1 is 1), or VC3/1 when the input is
SYSCLK, or SYSCLKX2 is not allowed.
Bit 5: AUXEN.
The AUXEN bit enables the Auxiliary output
to be driven onto the selected row output. If the selected
function is SPI Slave, the meaning of this bit is different. The
SPI Slave does not have a defined Auxiliary output, so this
bit is used, in conjunction with the AUX IO Select bits to con-
trol the Slave Select input signal (SS_). When this bit is set,
the SS_ input is forced active; and therefore,
from an input pin is unnecessary.
Bits 4 and 3: AUX IO Select[1:0].
These two bits select
one (out of the four) row outputs to drive the Auxiliary output
onto. In SPI Slave mode, these bits are used in conjunction
with the AUXEN bit to control the Slave Select (SS_) signal.
In this mode, these two bits are used to select one of four
row inputs for use as SS_. If no SS_ is required in a given
application, the AUXEN bit can be used to force the SS_
input active; and therefore, routing SS_ in through a Row
Input is not required.
Bit 2: OUTEN.
This bit enables the Primary output to be
driven onto the selected row output.
Bits 1 and 0: Output Select[1:0].
These two bits indicate
which of the four row outputs the Primary output will be
driven onto.
For additional information, refer to the
.
Table 17-26. Digital Block Output Definitions
Function
Outputs
Primary
Auxiliary
Interrupt
Timer
Terminal Count
Compare
Terminal Count or
Last-shot or Com-
pare True or Cap-
ture or KILL
Counter
Compare
Terminal Count
Terminal Count or
Last-shot or Com-
pare True or KILL
Dead Band
Phase 1
Phase 2
Phase 1 or KILL
PWMDBL
Phase 1
Phase 2
Phase 1 or KILL
CRCPRS
MSB
Compare
Compare or DS or
KILL
SPIM
MOSI
SCLK
TX Reg Empty or
SPI Complete
SPIS
MISO
N/A **
TX Reg Empty or
SPI Complete
Transmitter
TXD
SCLK *
TX Reg Empty or
TX Compete
Receiver
RXD
SCLK *
RX Reg Full
DSM
Multiplication
Density Signal
Density Signal or
KILL
Table 17-27. AUXCLK Bit Selections
Code
Description
Usage
00
Bypass
Use this selection only when SYSCLKX2 (48
MHz) is selected by the 16-to-1 clock multiplexer
(see the DxCxxIN register).
01
Resynchronize
to SYSCLK
(24 MHz)
This is a typical selection. Use this setting for any
SYSCLK-based clock: VC1, VC2, VC3 driven by
SYSCLK, digital blocks with SYSCLK based
source clocks, broadcast bus with source based
on SYSCLK, row input and row outputs with
source based on SYSCLK.
10
Resynchronize
to SYSCLKX2
(48 MHz)
Use this setting for any SYSCLKX2-based clock:
VC3 driven by SYSCLKX2, digital blocks with
SYSCLKX2 based source clocks, broadcast bus
with source based on SYSCLKX2, row input and
row outputs with source based on SYSCLKX2.
11
SYSCLK
Direct
Use this setting to clock the block directly using
SYSCLK. Note that this setting is not strictly
related to clock resynchronization: because SYS-
CLK cannot resynchronize itself, it allows a direct
skew controlled SYSCLK source.
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 ...
Страница 317: ...316 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G ...
Страница 393: ...392 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G ...
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 ...
Страница 561: ...560 CY8C28xxx PSoC Programmable System on Chip TRM Document No 001 52594 Rev G ...