Functional overview
STM32F042xx
DocID025832 Rev 2
3.16
Serial peripheral interface (SPI)/Inter-integrated sound
interfaces (I
2
S)
Up to two SPIs are able to communicate up to 18 Mbits/s in slave and master modes in full-
duplex and half-duplex communication modes. The 3-bit prescaler gives 8 master mode
frequencies and the frame size is configurable from 4 bits to 16 bits.
One standard I
2
S interface (multiplexed with SPI1) supporting four different audio standards
can operate as master or slave at half-duplex communication mode. It can be configured to
transfer 16 and 24 or 32 bits with 16-bit or 32-bit data resolution and synchronized by a
specific signal. Audio sampling frequency from 8 kHz up to 192 kHz can be set by an 8-bit
programmable linear prescaler. When operating in master mode, it can output a clock for an
external audio component at 256 times the sampling frequency.
for the differences between SPI1 and SPI2.
LIN mode
X
Dual clock domain and wakeup from Stop mode
X
Receiver timeout interrupt
X
Modbus communication
X
Auto baud rate detection
X
Driver Enable
X
X
1. X = supported.
2. USART1_CK is not available on 20/28 pin packages. Another source of clock (for example timer output
programmed to the desired clock frequency) is needed to clock the card.
Table 10. STM32F042x USART implementation (continued)
USART modes/features
(1)
USART1
USART2
Table 11. STM32F042x SPI/I2S implementation
SPI features
(1)
1. X = supported.
SPI1
SPI2
Hardware CRC calculation
X
X
Rx/Tx FIFO
X
X
NSS pulse mode
X
X
I2S mode
X
TI mode
X
X
