TOOLSTICK560DC Silicon Laboratories Inc, TOOLSTICK560DC Datasheet - Page 236

• Manufacturer Part Number: TOOLSTICK560DC
• Description: DAUGHTER CARD TOOLSTICK F560
• Manufacturer: Silicon Laboratories Inc
• Series: ToolStickr
• Type: MCUr

Specifications of TOOLSTICK560DC

• Contents: Daughter Card
• Processor To Be Evaluated: C8051F55x, C8051F56x, C8051F57x
• Interface Type: USB
• Operating Supply Voltage: 2.7 V to 3.6 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051F55x, C8051F56x, C8051F57x
• For Use With: 336-1345 - TOOLSTICK BASE ADAPTER336-1182 - ADAPTER USB DEBUG FOR C8051FXXX
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1719

C8051F55x/56x/57x
23.3. Configuration and Operation
UART0 provides standard asynchronous, full duplex communication. It can operate in a point-to-point
serial communications application, or as a node on a multi-processor serial interface. To operate in a point-
to-point application, where there are only two devices on the serial bus, the MCE0 bit in SMOD0 should be
cleared to 0. For operation as part of a multi-processor communications bus, the MCE0 and XBE0 bits
should both be set to 1. In both types of applications, data is transmitted from the microcontroller on the
TX0 pin, and received on the RX0 pin. The TX0 and RX0 pins are configured using the crossbar and the
Port I/O registers, as detailed in Section “19. Port Input/Output” on page 167.
In typical UART communications, The transmit (TX) output of one device is connected to the receive (RX)
input of the other device, either directly or through a bus transceiver, as shown in Figure 23.5.
23.3.1. Data Transmission
Data transmission is double-buffered and begins when software writes a data byte to the SBUF0 register.
Writing to SBUF0 places data in the Transmit Holding Register, and the Transmit Holding Register Empty
flag (THRE0) will be cleared to 0. If the UART’s shift register is empty (i.e., no transmission in progress),
the data will be placed in the Transmit Holding Register until the current transmission is complete. The TI0
Transmit Interrupt Flag (SCON0.1) will be set at the end of any transmission (the beginning of the stop-bit
time). If enabled, an interrupt will occur when TI0 is set.
If the extra bit function is enabled (XBE0 = 1) and the parity function is disabled (PE0 = ‘0’), the value of the
TBX0 (SCON0.3) bit will be sent in the extra bit position. When the parity function is enabled (PE0 = 1),
hardware will generate the parity bit according to the selected parity type (selected with S0PT[1:0]), and
append it to the data field. Note: when parity is enabled, the extra bit function is not available.
23.3.2. Data Reception
Data reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to logic 1. After the
stop bit is received, the data byte will be stored in the receive FIFO if the following conditions are met: the
receive FIFO (3 bytes deep) must not be full, and the stop bit(s) must be logic 1. In the event that the
receive FIFO is full, the incoming byte will be lost, and a Receive FIFO Overrun Error will be generated
(OVR0 in register SCON0 will be set to logic 1). If the stop bit(s) were logic 0, the incoming data will not be
stored in the receive FIFO. If the reception conditions are met, the data is stored in the receive FIFO, and
the RI0 flag will be set. Note: when MCE0 = 1, RI0 will only be set if the extra bit was equal to 1. Data can
be read from the receive FIFO by reading the SBUF0 register. The SBUF0 register represents the oldest
byte in the FIFO. After SBUF0 is read, the next byte in the FIFO is immediately loaded into SBUF0, and
space is made available in the FIFO for another incoming byte. If enabled, an interrupt will occur when RI0
is set. RI0 can only be cleared to ‘0’ by software when there is no more information in the FIFO. The rec-
ommended procedure to empty the FIFO contents is as follows:
236
Figure 23.5. Typical UART Interconnect Diagram
USB Port
PC
USB
MCU
RX
TX
Rev. 1.1
USB-to-UART
CP2102
Bridge
OR
RX
TX
TX
RX
C8051Fxxx
C8051Fxxx