NRF9E5 Datasheet, PDF (81/104 Pages) List of Unclassifed Manufacturers – 433/868/915MHz RF Transceiver with Embedded 8051 Compatible Microcontroller and 4 Input, 10 Bit ADC

PRODUCT SPECIFICATION
nRF9 E5 Single Chip Transceiver with Embedded Microcontroller and ADC
18.8.3.5 Baud Rate Generator Mode
Setting either RCLK or TCLK to 1 configures Timer 2 to generate baud rates for Serial
port in serial mode 1 or 3. In baud-rate generator mode, Timer 2 functions in auto-reload
mode. However, instead of setting the TF2 flag, the counter overflow generates a shift
clock for the serial port function. As in normal auto-reload mode, the overflow also
causes the preloaded start value in the RCAP2L and RCAP2H registers to be reloaded
into the TL2 and TH2 registers.
When either TCLK = 1 or RCLK = 1, Timer 2 is forced into auto-reload operation,
regardless of the state of the CP/RL2 bit.
When operating as a baud rate generator, Timer 2 does not set the TF2 bit. In this mode,
a Timer 2 interrupt can be generated only by a high-to-low transition on the t2ex pin
setting the EXF2 bit, and only if enabled by EXEN2 = 1.The counter time base in baud-
rate generator mode is CPU_clk/2. To use an external clock source, set C/T2 to 1 and
apply the desired clock source to the t2 pin.
CPU_CLK _{Divide by 2}
SCK/T2
TR2
EXEN2
LP_OSC _{Divide by 2}
Timer 1 overflow _{Divide by 2}
SMOD0
0
C/T2
0
1
1
clk ⁰
78
15
TL2
TH2
RCLK
RX
0
clock
Divide by 16
1
0
78
15
RCAP2L RCAP2H
TCLK
0
Divide by 16
1
TX
clock
INT
EXF2
Figure 23 Timer 2 – Baud Rate Generator Mode.
18.9 Serial Interface
The nRF9E5 is configured with one serial port, which is identical in operation to the
standard 8051 serial port. The two serial port pins rxd and txd are available as alternate
functions of P0.1 and P0.2, for details please see ch. 6.3 on page 15.
The serial port can operate in synchronous or asynchronous mode. In synchronous
mode, the nRF9E5 generates the serial clock and the serial port operates in half-duplex
mode. In asynchronous mode, the serial port operates in full-duplex mode. In all modes,
the nRF9E5 buffers receive data in a holding register, enabling the UART to receive an
incoming word before the software has read the previous value.
The serial port can operate in one of four modes, as outlined in Table 70.
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway -Phone [phone] - Fax [phone]
Revision: 1.1
Page 81 of 104
June 2004