nRF24E2 Nordic VLSI, nRF24E2 Datasheet - Page 75

• Manufacturer Part Number: nRF24E2
• Description: Single Chip RF Transmitter + MCU + ADC NRF2402 2.4GHz RF Transmitter
• Manufacturer: Nordic VLSI

PRODUCT SPECIFICATION
Baud Rate =
To use Timer 1 as the baud-rate generator, it is best to use Timer 1 mode 2 (8-bit
counter with auto-reload), although any counter mode can be used. The Timer 1
reload value is stored in the TH1 register, which makes the complete formula for
Timer 1:
Baud Rate =
The 4 in the denominator in the above equation can be obtained by setting the T1M bit
in the CKCON SFR. To derive the required TH1 value from a known baud rate (when
TM1 = 0), use the equation:
TH1 = 256 -
You can also achieve very low serial port baud rates from Timer 1 by enabling the
Timer 1 interrupt, configuring Timer 1 to mode 1, and using the Timer 1 interrupt to
initiate a 16-bit software reload. Table Table 10-20 lists sample reload values for a
variety of common serial port baud rates.
Desired
19.2 Kb/s
9.6 Kb/s
4.8 Kb/s
2.4 Kb/s
1.2 Kb/s
Table 10-20 : Timer 1 Reload Values for Serial Port Mode 1 Baud Rates
To use Timer 2 as the baud-rate generator, configure Timer 2 in auto-reload mode and
set the TCLK and/or RCLK bits in the T2CON SFR. TCLK selects Timer 2 as the
baud-rate generator for the transmitter; RCLK selects Timer 2 as the baud-rate
generator for the receiver. The 16-bit reload value for Timer 2 is stored in the
RCAP2L and RCA2H SFRs, which makes the equation for the Timer 2 baud rate:
Baud Rate =
where RCAP2H,RCAP2L is the content of RCAP2H and RCAP2L taken as a 16-bit
unsigned number. The 32 in the denominator is the result of the CPU_clk signal being
divided by 2 and the Timer 2 overflow being divided by 16. Setting TCLK or RCLK
to 1 automatically causes the CPU_clk signal to be divided by 2, as shown in Figure
10-7 : Timer 2 – Baud Rate Generator Mode, instead of the 4 or 12 determined by the
T2M bit in the CKCON SFR.
Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0
Baud Rate
32
Timer
2
128
32
SMOD
1
1
1
1
1
x
2
(65536
Baud
2
x
16
Overflow
4
-
Rate
x
{RCAP2H,
(256
C/T
0
0
0
0
0
clk
-
TH1)
Timer 1
Mode
RCAP2L})
QhtrÃ&$ÂsÃ(
2
2
2
2
2
TH1 Value
for 16 MHz
CPU clk
0xF3
0xE6
0XcC
0x98
0x30
TH1 Value
for 8 MHz
CPU clk
-
0xF3
0xE6
0xCC
0x98
August 2003