UNO setting up SPI for LTC6804

Projects Programming
1

Hello,

http://cds.linear.com/docs/en/datasheet/680412f.pdf
on page 41 of the datasheet it says:

DATA LINK LAYER
All Data transfers on LTC6804 occur in byte groups.
Every byte consists of 8 bits. Bytes are transferred with
themost significant bit (MSB) first. CSBmustremain low
forthe entire duration of a command sequence, including
betweenacommandbyteandsubsequentdata. Onawrite
command, data is latched in on the rising edge of CSB.

and on page 35

Timing
The 4-wire serial port is configured to operate in a SPI
systemusingCPHA = 1 andCPOL = 1. Consequently, data
on SDImust be stable during the rising edge of SCK. The
timing is depicted in Figure 15. The maximum data rate
is 1Mbps.

Is this the correct setup then ?

 SPI.setBitOrder(MSBFIRST);
 SPI.setClockDivider(SPI_CLOCK_DIV32); // should be fast enough
 SPI.setDataMode(SPI_MODE3);

How to calculate data rate to MHZ ? Assuming it means i can send a 10^6 bytes in one second i would say that 1Mbps = 8Mhz ?

sidenote: http://arduino.cc/de/Reference/SPIEnd Will it pull SS down again?

2

First check the datasheet - a 5k pull up resistor is needed on one of the SPI pins.

Secondly all SPI transfers begin by bringing CS low, then transfering a number of bytes, then
set CS high again.

For bus speed the MHz is always the wire speed, bits per second, not bytes. Thus 1MHz means
a 1MHz SCLK (8 us per byte transferred).