4-50
AT90S8414
Preliminary
THE SPI DATA REGISTER - SPDR
Bit
7
6
5
4
3
2
1
0
$0F
MSB
LSB
SPDR
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
The SPI Data Register is a read/write register used for data transfer between the register file and the SPI Shift register.
Writing to the register initiates data transmission. Reading the register causes the Shift Register Receive buffer to be read.
The UART
The AT90S8414 features a full duplex Universal Asynchronous Receiver and Transmitter (UART). The main features
are:
·
Baud rate generator generates any baud rate
·
High baud rates at low XTAL frequencies
·
8 or 9 bits data
·
Noise filtering
·
Overrun detection
·
Framing Error detection
·
False Start Bit detection
·
Three separate interrupts on TX Complete, TX Data Register Empty and RX Complete
Data Transmission
A block schematic of the UART transmitter is shown in Figure 42.
