nRF24E1 Nordic VLSI, nRF24E1 Datasheet - Page 79

• Manufacturer Part Number: nRF24E1
• Description: 2.4Ghz RF Transceiver With Embedded 8051 Compatible Microcontroller And 9 Input, 10 Bit ADC
• Manufacturer: Nordic VLSI

PRODUCT SPECIFICATION
Bit
SCON.7
SCON.6
SCON.5
SCON.4
SCON.3
SCON.2
SCON.1
Table 10-20 : SCON Register – SFR 0x98
Serial mode 0 provides synchronous, half-duplex serial communication. For Serial
Port 0, both serial data input and output occur on
clock for both transmit and receive. The
Port 0, please also see Table 3-2 : Port 0 (P0) functions for port and pin configuration.
The lack of open drain ports on nRF24E1 makes it a programmer responsibility to
control the direction of the rxd pin.
The serial mode 0 baud rate is either CPU_clk/12 or CPU_clk/4, depending on the
state of the SM2. When SM2 = 0, the baud rate is CPU_clk/12; when SM2 = 1, the
baud rate is CPU_clk/4.
Mode 0 operation is identical to the standard 8051. Data transmission begins when an
instruction writes to the SBUF SFR. The UART shifts the data out, LSB first, at the
selected baud rate, until the 8-bit value has been shifted out.
Mode 0 data reception begins when the REN bit is set and the RI bit is cleared in the
corresponding SCON SFR. The shift clock is activated and the UART shifts data in
on each rising edge of the shift clock until eight bits have been received. One machine
cycle after the 8
software clears the RI bit.
Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0
Function
SM0 - Serial port mode bit 0.
SM1 - Serial port mode bit 1, decoded as:
SM0
SM2 - Multiprocessor communication enable. In modes 2 and 3, SM2 enables the
multiprocessor communication feature. If SM2 = 1 in mode 2 or 3, RI will not be
activated if the received 9
if a valid stop is received. In mode 0, SM2 establishes the baud rate: when SM2 = 0,
the baud rate is CPU_clk/12; when
SM2 = 1, the baud rate is CPU_clk/4.
REN - Receive enable. When REN = 1, reception is enabled.
TB8 - Defines the state of the 9
RB8 - In modes 2 and 3, RB8 indicates the state of the 9
RB8 indicates the state of the received stop bit. In mode 0, RB8 is
not used.
TI - Transmit interrupt flag. Indicates that the transmit data word has been shifted
out. In mode 0, TI is set at the end of the 8
when the stop bit is placed on the txd pin. TI must be cleared by the software.
0
0
1
1
th
bit is shifted in, the RI bit is set and reception stops until the
SM1 Mode
0
1
0
1
0
1
2
3
th
bit is 0. If SM2 = 1 in mode 1, RI will be activated only
QhtrÃ&(ÂsÃ(&
th
rxd
data bit transmitted in modes 2 and 3.
and
th
txd
rxd
data bit. In all other modes, TI is set
pins are alternate function bits of
pin, and
th
bit received. In mode 1,
txd
provides the shift
July 2003