mc33596 Freescale Semiconductor, Inc, mc33596 Datasheet - Page 10

• Manufacturer Part Number: mc33596
• Description: Pll Tuned Uhf Receiver For Data Transfer Applications
• Manufacturer: Freescale Semiconductor, Inc

Register Access through SPI
Table 5
The data transfer protocol for each mode is described in the following sections.
10.2 Configuration Mode
This mode is used to write or read the internal registers of the MC33596.
As long as a low level is applied to CONFB (see
input, the MOSI line input, and the MISO line output. Whatever the direction, SPI transfers are 8-bit based
and always begin with a command byte, which is supplied by the MCU on MOSI. To be considered as a
command byte, this byte must come after a falling edge on CONFB.
command byte.
Bits N[1:0] specify the number of accessed registers, as defined in
Bits A[4:0] specify the address of the first register to access. This address is then incremented internally
by N after each data byte transfer.
10
•
Bit Name
MISO — (Master Input) Slave Output
Transmits data when slave, with the MSB first. There is no master function. Data are valid on
falling edges of SCLK. This means that the clock phase and polarity control bits of the
microcontroller SPI have to be CPOL = 0 and CPHA = 1 (using Freescale acronyms).
Configuration
Transmit
Receive
Standby / LVD
summarizes the serial digital interface feature versus the selected mode.
Selected Mode
Table 5. Serial Digital Interface Feature versus Selected Mode (SEB = 1)
DME = 1
DME = 0
Bit 7
N1
SPI slave, data received on MOSI, SCLK from MCU, MISO is output
SPI deselected, MOSI receives encoded data from MCU
SPI master, data sent on MOSI with clock on SCLK
SPI deselected, received data are directly sent to MOSI
SPI deselected, all I/O are high impedance
Bit 6
N0
N[1:0]
Table 6. Number N of Accessed Registers
00
01
10
11
Bit 5
Figure 3. Command Byte
MC33596 Data Sheet, Rev. 3
A4
Number N of Accessed Registers
Figure
MC33596 Digital Interface Use
Bit 4
A3
27), the MCU is the master node driving the SCLK
1
2
4
8
Bit 3
A2
Table
Figure 3
Bit 2
A1
6.
shows the content of the
Bit 1
A0
Freescale Semiconductor
Bit 0
R/W