SPI
Constructors
SPI(unit_id[required], baudrate[optional], polarity[optional], phase[optional], databits[optional], firstbit[optional], miso[optional], mosi[optional], sck[optional], mode[optional])
Create a SPI object and configure it using other parameters. This allows you to then read/write data on the SPI bus.
unit_id: The unit ID of the hardware SPI, assume default value if left blank
baudrate: The speed of SPI
polarity: one of factor determining SPI mode. (deprecated)
phase: one of factor determining SPI mode. (deprecated)
databits: number of data bits
Firstbit: this determine whether first bit is MSB or LSB
miso: miso pin. (deprecated)
mosi: mosi pin. (deprecated)
sck: clock pin. (deprecated)
mode: either MASTER mode or SLAVE mode
Note: All optional parameters have default values as follows,
Parameter |
Default |
|---|---|
Baudrate |
2000000 Hz |
Polarity |
Inactive_low |
Phase |
Toggle_middle |
Databits |
8 |
Firstbit |
MSB |
Miso |
N.A. |
Mosi |
N.A. |
Sck |
N.A. |
Mode |
MASTER |
There is currently 2 set of SPI, they are,
unit |
MOSI |
MISO |
SCK |
CS |
|---|---|---|---|---|
0 |
PB_18 |
PB_19 |
PB_20 |
PB_21 |
1 |
PB_4 |
PB_5 |
PB_6 |
PB_7 |
Note: both unit support master mode, but only unit 0 supports slave mode.
Methods
SPI.read()
This method waits and read data received in SPI buffer, then return the data received. Works in both master and slave mode.
SPI.write( value[required])
This method writes an integer value to SPI bus. Works in both master and slave mode.
value: an integer value to be sent on SPI bus