C8051F326DK Silicon Laboratories Inc, C8051F326DK Datasheet - Page 122

• Manufacturer Part Number: C8051F326DK
• Description: KIT DEV FOR C8051F326/7
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F326DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F326/F327
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F326
• Silicon Family Name: C8051F32x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Silicon Laboratories C8051F326, C8051F327
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1306

C8051F326/7
enabled, the value of the stop bit for the oldest FIFO byte will be presented in RBX0. When the parity func-
tion is enabled (PE0 = ‘1’), hardware will check the received parity bit against the selected parity type
(selected with S0PT[1:0]) when receiving data. If a byte with parity error is received, the PERR0 flag will be
set to ‘1’. This flag must be cleared by software. Note: when parity is enabled, the extra bit function is not
available.
13.3.3. Multiprocessor Communications
UART0 supports multiprocessor communication between a master processor and one or more slave pro-
cessors by special use of the extra data bit. When a master processor wants to transmit to one or more
slaves, it first sends an address byte to select the target(s). An address byte differs from a data byte in that
its extra bit is logic 1; in a data byte, the extra bit is always set to logic 0.
Setting the MCE0 bit (SMOD0.7) of a slave processor configures its UART such that when a stop bit is
received, the UART will generate an interrupt only if the extra bit is logic 1 (RBX0 = 1) signifying an
address byte has been received. In the UART interrupt handler, software will compare the received
address with the slave's own assigned address. If the addresses match, the slave will clear its MCE0 bit to
enable interrupts on the reception of the following data byte(s). Slaves that weren't addressed leave their
MCE0 bits set and do not generate interrupts on the reception of the following data bytes, thereby ignoring
the data. Once the entire message is received, the addressed slave resets its MCE0 bit to ignore all trans-
missions until it receives the next address byte.
Multiple addresses can be assigned to a single slave and/or a single address can be assigned to multiple
slaves, thereby enabling "broadcast" transmissions to more than one slave simultaneously. The master
processor can be configured to receive all transmissions or a protocol can be implemented such that the
master/slave role is temporarily reversed to enable half-duplex transmission between the original master
and slave(s).
122
RX
Master
Device
Figure 13.6. UART Multi-Processor Mode Interconnect Diagram
TX
RX
Device
Slave
TX
Rev. 1.1
RX
Device
Slave
TX
RX
Device
Slave
TX
V+