MC33780 Datasheet, PDF (22/37 Pages) Freescale Semiconductor, Inc – Dual DBUS Master with Differential Drive and Frequency Spreading

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
CLK_VCO0
CLK
INT
RST
MISO
SCLK
CS
MOSI
Channel 0
Clock Select and Divider
SPI & Registers
Int err upt
status regs
control regs
enable regs
poly regs
seed regs
length regs
SS ctrl regs
SS offset regs
SS Up/Dwn regs
register pointer
bit pointer
Bit Clock 0
RX0 Data
RX0 Status
TX0 Data
TX0 Status
RX1 Data
RX1 Status
SPI XFER
TX1 Da ta
TX1 Status
RX FIFO
RX Buffer
RX Buffer
RX Buffer
RX Buffer
TX FIFO
TX Buffer
TX Buffer
TX Buffer
TX Buffer
RX FIFO
RX Buffer
RX Buffer
RX Buffer
RX Buffer
TX FIFO
TX Buffer
TX Buffer
TX Buffer
TX Buffer
CH0
CH0 Enable
CH1 Enable
CH1
CLK_VCO1
CLK
Channel 1
Clock Select and Divider
Bit Clock 1
Figure 18. Logic Block Diagram
LOGIC BLOCK DIAGRAM DESCRIPTION
Figure 18, Logic Block Diagram, shows a block diagram of
the major logic blocks in the IC.
SPI
The SPI is a standard serial peripheral interface. This
interface provides two-way communications between the IC
and an MCU. The MCU can write to registers that control the
operation of the IC and read back the conditions in the IC
using the SPI. It can also write data to be sent out on the
DBUS and read data that was returned on the DBUS. The
register pointer and bit pointer are used to control which
registers and bits are being written to and read from using the
SPI. Its operation is described in detail in the section entitled
SPI Communications.
REGISTERS
The register set consists of control, status, transmit, and
receive types. They are written and read using the SPI
interface and are affected by events in the IC. Detailed
descriptions of their operation and use can be found
throughout later sections of this data sheet.
INTERRUPT
The Interrupt block controls the INT output terminal. The
main purpose of the Interrupt is to quickly inform the MCU
when data has been received via the DBUS or when the
33780
22
Analog Integrated Circuit Device Data
Freescale Semiconductor