
S E R I A L C O N T R O L M O D U L E : H D L C
DPLL operation: Adjustment ranges and output clocks
420
Hardware Reference NS9215
NRZ and NRZI
encoding
With NRZ and NRZI encoding, all transitions occur on bit-cell boundaries and the data
should be sampled in the middle of the bit cell.
If a transition occurs after the expected bit-cell boundary, but before the
midpoint, the DPLL needs to lengthen the count to line up the bit-cell
boundaries; this corresponds to the “add one” and “add two” regions of the
figure.
If a transition occurs before the bit-cell boundary, but after the midpoint, the
DPLL needs to shorten the count to line up the bit-cell boundaries; this
corresponds to the “subtract one” and “subtract two” regions shown in the
figure.
The DPLL makes no adjustment if the bit-cell boundaries are lined up within
one count of the divide-by-sixteen counter. The regions that adjust the count
by two allow the DPLL to synchronize faster to the data stream when starting
up.
Biphase-Level
encoding
With biphase-level encoding, there is a guaranteed “clock” transition at the center of
every bit-cell and optional “data” transitions at the bit-cell boundaries. The DPLL
NRZI adj
NRZI Clock
Bi-L adj
Bi-L Clock
Bi-S adj
Bi-S Clock
Bi-M adj
Bi-M Clock
Bit cell
add one
add two
subtract two
subtract one
none
none
ignore transitions
subtract one
none
add one
ignore transitions
ignore transitions
none
add one
subtract one
none
ignore transitions
none
add one
subtract one
none
Содержание NS9215
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Страница 26: ...26 Hardware Reference NS9215...
Страница 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Страница 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Страница 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Страница 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Страница 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Страница 260: ...M E MO R Y C O N T ROL L E R StaticMemory Turn Round Delay 0 3 registers 260 Hardware Reference NS9215...
Страница 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Страница 362: ...A E S D AT A E N C R Y P T I O N D E C R Y P T I O N M O D U L E CCM mode 362 Hardware Reference NS9215...
Страница 384: ...I O HU B M OD UL E Module Direct Mode TX Data Last FIFO 384 Hardware Reference NS9215 31 March 2008...
Страница 414: ...S E R I A L C ON T RO L M O D U L E U ART UART Modem Status register 414 Hardware Reference NS9215...
Страница 446: ...S E R I A L C ON T RO L M O D U L E S PI SPI timing characteristics 446 Hardware Reference NS9215...
Страница 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Страница 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Страница 514: ...PA CKA GING Processor Dimensions 514 Hardware Reference NS9215 P r o c e s s o r D i m e n s i o n s...
Страница 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Страница 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...